Same barrel.
The slide is different.
The D.E. disconnector is a projection from the DA trigger drawbar on the right side of the frame. Its slide cut is in the side rail, not the center feed rail. A G.M. slide can have the D.E. disconnector cut made, the regular centerline cut just doesn't do anything in the D.E. I know people who have done it. I guess you could modify a D.E. slide to work on a G.M., but there are not so many around that the situation comes up.
I don't know about the small parts. The extractor looks right in the diagram, but the firing pin doesn't. But they are just drawings so I can't be sure; check part numbers if you care enough.
