I'm not sure where the tabs are you're talking about. There are two "tabs" that stick up to block the bridge track from the spots where the turning mechanism is. Anyway my guess would be 1. the tabs may be there to hold the rotating part of the turntable in place and 2. it probably does serve a purpose so I would be hesitant to remove them.
www.atlasrr.com
There are three plastic "tabs" that stick out from the drive portion of the Atlas TT and intrude onto the brown plastic turntable itself. Do they serve any purpose or can they be eliminated?
Bear "It's all about having fun."