Well, I think I have run accross them on Ebay before. When they say Teflon coating, the only ones I know of that teflon coat is DPMS (IIRC).
Any how, the ones listed on the auction says they have cosmetic blemishes. So they are number 2 uppers....
A Rock River stripped flat top goes for about $100.00 and the upper parts to finish it is about 18.25. And the ready to go upper (minus the chargine handle) is 115.00 from Rock River.
I've never tried those uppers. IF you can get them "cheap" and all the probem is the finish, great. But know what you are bidding on and how much the "good" stuff costs.... or you might get into a bidding war and end up paying the same for complete uppers and number 1's for a number 2 upper receiver.
One time, one of the dealers here were selling A3 complete (by Rock River) for about 89-100. But that was some time....look in the EE for them..... never know what you will find.