Bob,
Thanks for your questions--- I'll try to do the best I can.
1. The acceptance stamps on the right receiver are two large E/63's followed by the Eagle proof.
2. I have read of the "Mauser Hump", but have not been able to figure this out.
Hopefully one of you can educate me on this.
3. I don't think the grips are original to the pistol,
and appear to be Erfurt s/n 19. Couldn't tell you the diff between Mauser grips and others.
4. Re: the bbl. The acceptance stamp is SMALL E/63 on the left side, and Small eagle proof on the right. The bbl S/N and receiver S/N match well in size and font. I would say that there is a difference in the blue from the bbl and the receiver. The bbl is brighter and higher polished than the receiver.
5. The mag is NOT navy marked. It is blue, Alum base S/N 4542, looks like a "t" suffix,with small E/63 acceptance mark.
Hope this helps.----
Ronnie