What I can see - DWM (maker in germany from 1900-1930)
**what is the caliber? - I expect it to be 9mm Luger, but you can show the underside of the barrel, it would have xxxx (serial number) and under that 8,82 or a number close to that - that is the land to land grooves.
Is it marked Germany anywhere? I expect it not to say that
And is that rust or gunk on the right side? Rust that much can be removed, but I would leave it alone
If it came by my table at a show, I'd offer $500 without ascertaining much about it - more as I figured it out

But, without matching grips, without a magazine, not much more than $600-700