Re: WWII era 98 mauser help
Nice rifle!
Danzig was the state arsenal in what is now Gdansk, Poland. Danzig became Gdansk after WWII. The Poles built rifles for themselves after WWII but moved the Danzig equipment to Warsaw. That is why you still see Danzig on there. It would have to be an arsenal re-work with a date of 1935. There is also the possibility that says 1915, in which case it would be original.
However, the rifle is not original and there is nothing unique about it other than the features added to it are, as mentioned above, from the late forties through early sixties. So, price-wise it isn't going to bring a whole bunch. It certainly would be a rifle I'd like to have though.
If you can get hold of some used 8mm brass and some 30-06 brass and see what it is chambered in now. Take a sharpie and color the entire shoulder and maybe some lines up the neck and down the body, to see where the chamber hits. If none of that makes sense a gunsmith can do a cerro-cast of the chamber for you. Or, you can do it too. Then measure what you have.
I've got a bunch of old rebuilt Mausers and some of them shoot incredibly well. do yourself a favor and find out what this is and get a scope on it and shoot it. You'll be surprised at how good they are.