Depends on the profile of the barrel itself. If you have a lightweight profile barrel or a standard "government profile". Obviously, the lightweight will use the smaller diameter FSB.
This here says that it's Government Profile but does not specify .625 or .750 and the Bravo gas blocks don't specify if which profile they fit other then my dimension, .625 or .750.
I just sent them an email but I get the feeling it's going to be a few days before I hear back.