Pictures would be lovely.

In short answer : Yes, but you shouldn't.

Long answer:
It can be used for mining, however the design of all Nvidia chip GPU's don't work well compared to ATI, due to their differences at a hardware level.
At a software level, the mining process mostly uses OpenCL to make use of the "Shaders" (hardware) on the GPU. Nvidia and ATI both have these, but Nvidia took the approach of a few complex ones and ATI too the approach of lots of simple ones. The mining process is relatively simple, thus having lots of simple shaders is very efficient for this task. Nvidia more complex shaders in some areas are less efficient and thus far there has been no way to compensate for that. There is in the region 5-10 less bitcoins generated out of a similar power (watt) consuming processor between nvidia and ati. This makes Nvidia GPU's so inefficient you actually spending money to make these bitcoins rather than turning a profit, which generally speak you will always do on an ATI GPU.
Both GPU markers, choose these different paths quiet a few years ago and ATI kept theirs when they realise they had adopted a secondary market outside of gamers, Nvidia already had the TELSA to bring in the more Scientific use of GPU so were not going to change their design.

I have a 1939 Mauser Karabiner 98 Kurz in 7.62 (converted by the Norwegian Army after the war) with all original emblems and Whermacht serials. Would this be interesting at all?

Pic is the emblems, original SN crossed over but all other emblems are intact. Added are Norwegian armory SN and HÆR for branch designation (Army). You'd have to fix the importpapers yourself, which i guess would be the catch here