Hello and welcome
Here is some basic info, made in 1917 (year stamp) by DWM
It probably had very bad oil stains and when it was refinished (here in the USA, not an arsenal), someone probably tried to clean the grips and those stains were left.
It has been reblued, you can tell by the glossy of the finish and the lightness of the stampings.
also, the prong like thing that attaches to the mainspring is not attached (you can tell the toggle is not in its correct position)
I collect bringback stories, if you know how the family member got it? Then email me if you'd like
Ed