Sometimes its not THAT expensive. Quite often, the seller doesn't bother to find out what it is they are selling.
Below is my Performance Center 45CQB Prototype. One of one. PCZ serial prefix. Used in the American Handgunner article on same in 2001. Purchased from a pawn shop in MD for not much more than a standard 3rd gen 45 - at the time.
A friend recently purchased a Performance Center compensated 40 from a large, well known gunshop in Charlotte. One of 25 or so made. For the sum of $475 + tax. THAT shop should have known better. Regards 18DAI