Yeah, $160 is spendy for a 1/24 diecast model. It's rare only because they didn't produce that many, but it's of a recent production run from 2003.
I have a few choice diecast pieces myself, and prefer the larger scales, but if word of these Columbo rigs had ever reached my ear, I'd have one.
That's what makes me think they weren't intended for widespread distribution, or the few they did make sold out fast. I like the scale figure they included with it too, and the replica itself isn't a bad one.