has correct aperture but an A2 dust cover (from the factory, I bought the parent rifle new in 1986-87).
$105- shipped and insured.
EDIT-it about 80% finish, light grey like the SP-1 should be.
C-7 upper (an A2 upper with A1 sights)-perhaps a Bushmaster upper, don't know for sure. Round F/A, A-2 port cover. Works on large hole lower, black finish, hole isn't perfect but not looser than half the AR's I see at the stores. A2 aperture. It has worked well for me.
looks like this, except mine has A2 forward assist-www.bushmaster.com/shopping/uppers/a1ur.asp]www.bushmaster.com/shopping/uppers/a1ur.asp
$105- shipped and insured