Yes! If you Google "Brownells Two Piece AR Gas Block". You will see they have a couple of styles. They attach with four hex screws. The one I have has the Picatinny Rail on the top and the bottom. But they also have on with the Picatinny Rail on the top and Bayonet Lug on the bottom.
The Constitution is not an instrument for the Government to restrain the people. It is an instrument for the people to restrain the Government!
“Americans have the right and advantage of being armed. Unlike the people of other countries, whose leaders are afraid to trust them with arms.”
James Madison. Author of the 2nd Amendment