Gen 3's are occasionally available, it's reputed by some that the smaller stores seem to get the few overruns from contracts. Interesting that a Cabela's had it.
They are common on auction sites and there are still police trade ins tricking in as smaller departments or officer owned guns are sold off. Bidding is about half of new retail on the holster worn guns. If anything some retailers will not accept anything but their reserve price as a starting bid so you will see some guns sitting idly in the bids over and over again, no one is attempting to buy them at the prices. You have to look at actual sold guns with a buyer to see that - which requires pulling up each individual listing to prove it's just not another actionless relist. Relists inflate the actual sale price if you don't look further. Guns that are selling are cheaper.
The Police trade-ins that sold for $329 ten and five years ago still are - you just have to look for them and expect only one in stock. Don't wait. I just recently passed on a 457 with a buy it now price of $300 shipping included. Others report gun stores tired of hanging on to them making deals to get some cash flow. The market is all about black plastic right now, if you want an old school stainless gun buy NOW before the last of them are gone and it's a resellers' market.
With .45ACP look for models 645, 4506, 4566, 457. S&W model numbers don't follow much convention and it can be confusing with the different barrel lengths, alloy frames, and optional features.