"triangular front stocks would be a pre ban unless some hack installed them.so how can that be a rip off."
Because you cannot legally put an original preban upper on a postban lower. You would have to at least mill off the bayonnet lug. As for the "birdcage" or prong type flash supressor, I'm not sure if you could leave them on. According to the info given, the lower is a post ban.
Regardless, I meant it as a joke.
Hube,
The uppers are just as reliable. The major differences are the sighting systems. With the A2 sights you can turn an adjustment wheel for elevation. That can make shooting distant targets easier by allowing you to hold normally on a target. The A2 model also has an integrated brass deflector. Unless you are a lefty, it really doesn't matter much. The A2 also has a round forward assist button instead of the teardrop type. Both styles work equally well.
The price you mentioned isn't bad. I would be sure you want that specific setup before purchasing it. The A2 uppers are a bit easier to trade if you aren't exactly happy with it or want a flatop upper later. With the A1 upper you may lose a bit in the trade. If you are like me..you won't be happy without a flatop!..thats my next project.
Good SHooting
RED