"IIRC, they dropped the bayonet lug as a feature on the Sporter
before they were required to do so, by the 1994 AW Law."
My 9mm AR doesn't have a bayonet lug. If it did, it would be strictly for decoration. With the 16" barrel and short handguards the bayonet would only stick out about 3"-4" past the barrel.
I also have a couple uppers with the 11.5" barrel and the 5" flash suppressor. They have bayonet lugs, but again, you can't actually use a bayonet with them. The flash suppressor is too big in diameter.
I am against these evil features bans as much as the next guy, but I honestly don't care about having a bayonet lug. Especially when it wouldn't work anyway.