Hopefully this isn't one of those situations that requires an arbor press to press it off.
Yea hopefully someone didn't press it on. 
does anyone know how to remove the round piece on the ram?
From the ones I have seen, it is not threaded. There is a set screw on the left side of the ram that holds things in the hole in the ram.
It is hard to believe that the round piece is part of the gear ram. If there is no fastener holding it, it must be pressed in. You can remove the faceplate then remove the whole gear ram assembly to inspect it more carefully.
You can remove the faceplate then remove the whole gear ram assembly to inspect it more carefully.
How do you know it wasn't an Atlantic operation?The company is in Michigan. Call them. I bet they made it for a pacific operation who needed it.