It's a DH 20 gauge

[B. Dudley]

Looks like a replacement stock. The checkering and comb does not look right.
The number matches on the guard, but it has been repaired. Maybe the original stock was broken through the wrist.

[Pittypatdugan]

I just cant believe that the long straight part of the trigger guard is a replacement to the original gun, the curved part looks different and may be

PDD

[Roundsworth]

A Damascus 20.....! (Sigh) Good on ya, Jeff! They are few and far between, I bet. Enjoy!