Spoken of quite alot here. The forward assist is too short to reach most .308AR BCG bodies. It wouldn't hit the BCG body serrations, even if they were there. However, it does catch the shoulder on the carrier body, as it transitions from smaller to larger. On the AR15, you could ratchet the carrier closed for the full length of those serrations. on the .308AR carrier. when it catches the shoulder, it would be the equivalent of the last two or so clicks on an AR15 carrier body.
True statement.
So, let's say you sell this carrier because it doesn't have serrations on the body, and you buy a new carrier that DOES have serrations on the body - the forward assist won't reach them anyway.