patton,
Look, if you guys mounted the M68 on the side, I'd really, really, really like to see it because, quite frankly that's asinine. I've been in for a while and have played with quite a few bits of equipment and tested a few and I've never heard of this.
What DTG did this occur?
Erick, you could zero it if someone did mount like that, but I just have a problem believing that such a mount was actually issued to a line unit. As far as offset optics are concerned, think about the Steyr AUG, with the optics built into the carrying handle.