Vergara from Spain here!
I'd say that the evidence provided in that article is almost conclusive. Many years ago I got in touch with Cortefiel and asked them whether Columbo's raincoat appeared in any of their catalogues fro the sixties, but they weren't able to find anything (funnily, very shortly afterwards, an article appeared somewhere about Columbo's coat having been made by Cortefiel, so it almost seemed as if I had given them the idea). On seeing the photos provided in that Japanese article, I'd say the raincoat that guy has found is exactly like Columbo's, which is not true of any Cortefiel raincoat I've ever seen (and, something I would have never expected, the "Prescription Murder" raincoat seems to be the same brand!). And I suppose the coat from the second run of the series cannot provide any clue, as it was a copy of the original one, though I don't suppose they copied even the brand label!
On reading joneil's post I was surprised at that bizarre name for a Spanish company, but on reading the Japanese article (well, on seeing its photos, rather) I've realised that the writer made a mistake, probably because he's not familiar with the Latin script. The real name of the company is "Costa de Majorca", not "Postade Majorca".
Though much more reasonable, this name is still weird. It's not English, but it's not Spanish, either. It's Spanglish. The Spanish name would be "Costa de Mallorca" (whose translation is "Coast of Majorca"), but no one here would use the English name of the island instead of the Spanish one (for those of you who don't know it, Majorca is a Spanish island in the Mediterranean, where tennis player Rafael Nadal is from).
So I felt slightly dubious about the Spanish origin of the company, of which I had never heard before. After googling it, I've found it mentioned in one of the issues of the Official State Gazette, from 15th March 1983, which includes it in a list of Spanish companies whose share capital is mostly foreign. Which, together with the Spanglish brand name, made me think of a company set up in Spain by someone not from here.
My next search has taken me to the Official Gazette of the United States Patent Office: Patents, Volume 912. Literally, it says:
"COSTA DE MAJORCA - The English translation of the Spanish words "Costa de Majorca" is "coast of Majorca". Owner of U.S. Reg. No. 776,227. For Rainwear for Men and Women (Int. Cl. 25). First use Aug. 3, 1962"
Lastly, I've found a publication called "Clipper Cargo Horizons" (A Pan Am World Trade Publicacion), which mentions "Costa de Majorca" in their November 1965 issue. On page 17 there is an article that goes like this:
"Rainwear From Spain Flies to Growing Markets
Two Americans in Spain have developed a growing export market for their luxury rainwear produced in a new and modern plant in Caspe, 150 kilometers west of Barcelona.
This rainwear from Spain goes mainly in the plane-flying to its biggest market, the United States, and also to a growing list of customers in such countries as the United Kingdom, Canada, France, Australia and Puerto Rico.
The five-year-old firm of Costa de Majorca produces only for export and not at all for the Spanish market. Presently about 90% of production goes to retailers in the U. S., but other foreign markets are expading as total sales rise every year.
In the U. S. market, Costa de Majorca sells directly to some 1,000 department stores and menswear specialty shops, using a force of 11 salesmen.
International air cargo is a vital marketing tool for the firm in serving its customers with the high-priced, high fashion product. In addition to customer service, air cuts insurance rates in half and, since the rainwear flies in cardboard containers, crating and packing savings are considerable.
The Costa de Majorca line ranges from a retail price of $60 for an all-weather cotton pima coat to a suede for $250 -or $750 with a mink fur lining.
All work at the Caspe plant is done by hand cutting, sewing, stitching, basting and such finishes tailoring as button holes.
Costa de Majorca is operated by the father and son team of Jerome and Steven Kropp. Jerome Kropp, a sports coat manufacturer in New York, became interested in the idea after a visit by a Spanish textile trade delegation in 1959. First product of the new Kropp enterprise in Spain was sports jackets too, but the switch to rainwear was made because of a wider range of material available for that line.
The Kropps have found that Spanish textile mills produce excellent suedes and cottons, particularly a fine, long-stapled pima suitable for rainwear manufacture.
Some 165 women are employed in the plant at Caspe, all hand tailoring specialists.
The junior member of the Costa de Majorca team, Steven Kropp, 25, heads the manufacturing operation and supervises the design of the new rainwear styles.
Not only is he fluent in the country's language, but has achieved national ranking in the sport of jai alai."
Well, apart from the small detail that Caspe is 225 km from Barcelona, not 150 km, it looks like the origin of Columbo's raincoat match well what is said here.
"Jai alai" is a game which has its origins in the north of Spain (though not in the Caspe area), but I haven't been able to find anyone called Kropp related to it. Neither have I found any reference to the Kropp factory in Caspe.
In my opinion, and after seeing the photos in the Japanese article and readin the Pan Am article, I'd be surprised if Columbo's raincoat weren't "Costa de Majorca". I suppose that someone (maybe Falk, or someone who saw the labels inside the coat) may have known it was made in Spain, and remember just that the brand name started with a C. Since Cortefiel was probably the best-known Spanish brand, it looks like someone jumped to the wrong conclusion.
(This is the most exciting piece of Columbo news for me in a long time!)