THe only real desireable German M1 Carbines are the Bavarians for the most part as they didn't have that penchant for mauser style sights as much as zee other Germans did. Too bad about that Saginaw. I have found a number of German M1's retain many of their original as-built parts, the first ones delivered not having gone through rebuild with the ones that remained in US inventories.
That Rock-ola is nice, as with what Contact said, price will depend upon the guts of the rifle, condition of the barrel, and markings throughout. From the pic though, it looks to be pretty nice!