Nope purely aesthetics.
Its kind of a crap gun anyways, somebody really screwed the pooch on giving that thing so much spread. Its a freaking BAR it shouldn't be inaccurate, it fires a powerful round from a long barrel it should be a tack driver.
The BAR was NOT a tack driver. An automatic rifle in that caliber cannot possibly be a tack driver, for the simple reason that it kicks like a mule. It was mainly used for suppression fire on the move- not to destroy targets with accurate fire, but to force the enemies to keep their heads down while US troops were advancing or retreating.
I liked the silenced Sniper Rifle on my first playthrough. Got annoyed with it on my second. The thing degrades VERY fast, and even with Jury Rigging the only cheap weapon that can repair it is the Service Rifle that's rather rare in the game.