1917 erfurt nazi era rebarrel?

[ink701]

hello,this is my 1st post...as well as my 1st luger..i have few p-38s,but finally stepped up to the plate....ahhem,..anyways...heres the question...i was at a local gun show and bought a 1917 erfurt,all matching numbers and correct proofs including the usual rc marks...matching numbers on the correct wood end ww1 era magazine as well....all except the barrel...the seller claimed it was a nazi era aresnal rebarrel..the barrel has a small waffenamp 655?...and a small "42" under the barrel near where it meets the frame...i liked the story,and possable history of the gun...the idea it saw service in both wars was cool,and the fact that the replaced barrel didnt have a full serial# from a diffrent gun made sense to me as an honest period rebarrel and not a post war parts change...anybody heard of these markings?....any feedback at all on this gun is much appriceated...i'm fully luger hooked now and look foward to my next find.....after doing more homework on this fine forum of course!...thank you.