Re: Drilling (Need some information)
Today Dieringhausen is in Nordrhein Westfălen, but I assume that when the gun was made it was in the Rheinland (Rhld.) In any case, as hrf says, it was never in East Germany, and the crown/W is the pre-WWII proofmark for a choked shotgun barrel.
The Crown/U was the definitive proof for arms proved in the finished state. All the marks on the shotgun barrels are correct for 16 gauge. The rifle barrel is marked 7.8 and 57, indicating chambering for 8x57JR or JRS, probably the former, but there is no way to be sure, so it would be best to assume that it is a JR and uses a .318" bullet rather than the JRS bullet at .323".
I doubt the gun was actually made in the Rhineland, it was probably made and proved in the Suhl area and the name on the rib is that of the retailer, not the manufacturer.
It appears to be a very good, though not the best quality gun; value would likely run about $4000, but others might be able to provide a better figure.