I have the badge of which you speak. It took a patch to make it work, after the patch I was able to make a Bronze Star on the Garand at which point the badge was awarded. I do have Specact and Veteran so I can confirm you definately need veteran and maybe Specact too. I'm now only three gold stars away from having Gold with all weapons which made the screw up with this irrelevant by the time it was resolved tbh.
As for the Bayonet, the Garand always makes me want to buttsmack the person in front of me Day of Defeat style instead of drawing my knife. Bayonets would be an awesome idea.