Yes, those that aren't promised to charity events/auctions or family members.
I had the chance to buy one of Stuart O'Grady's Looks (KG361 IIRC) some years ago, but he talked me out of it. Mostly, the team will sell a training bike with anything up to 30,000km on it in a season and that's not such a great deal, even if the price is good - which it usually is.
It depends on what you're looking for, obviously. I'll give you a hot tip which may be no help whatsoever. Get to Adelaide for the Tour Downunder in January, last year at least 4 teams I recall were selling bikes, gear, pretty much anything they could get a few bucks for. I saw Time team race bikes (not training) selling for A$3000.
They 'why' is simple. They were using the '07 gear, and hopping straight onto a plane for Europe, going straight back to the service course for the '08 issue of kit and equipment. Why carry the old stuff back through all those airports etc?
The only thing I ever drew a complete blank on was Lightweight wheels (d'oh) and getting Telekom kit; for some reason it was completely unavailable as merch and those Jerries were tight fisted geezers.