I vote to leave it alone. If you want to put a longer rail or something that actually requires a low profile gas block, shave your FSB. A few minutes will net you this:
Plus however long you want to spend prettying it up. I didn't worry about making it too perfect looking, as it's under the handguard. This way is cheap (free), easy, quick, and avoids the problems of a set screw or clamp on block.