Nice 1st model there baker. That's a German G96 sling on it. Actually they work very well if istalled like a normal K98sling as in my photos below. Just use the G96 sling buckle as the keeper and punch some holes in the end for adjustment and put in a brass button.
I don't have the button in this one because I just stuffed the sling in for the photo and didn't bother with the button.
Attachment 90976
Attachment 90977