I recently purchased a Colt 9mm upper, and there seems to be a small protrusion in the area where the forward assist normally would be. Is this normal?

Yes, it's normal on the 6951. It's just where they milled off the forward assist, albeit poorly, during production. I've seen it look cleaner... but also worse. I wouldn't worry about it.

Today's Colt doesn't seem to pay as much attention to detail as the Colt of days gone bye bye...

But I still buy 'em when I see a good deal!!

Thanks, I figured that was the case.