also did not think this sporter was build in germany
there is another M88 in 7x57 Mauser just now on gunbords having some similarity's with your rifle. the new owner have bought this rifle on gunbroker lately. I think the shape of the stock is very much like on your rifle.

http://forums.gunboards.com/showthread.p...al-7mm-Model-88

no doubt this was build by using a C.G.Haenel 7mm M 88 carbine for south america.