Well, I ended up buying it today. The old man sent the grips with a customer of his to have some custom ones made up, so he might be able to get those back.
The only markings I can find are "Steyr 1917" on the left side of the slide and a "k" on the rear of the slide, magazine follower and safety selector. It also has some sort of crest between a "W n" and "16" above the right side of the trigger. It has a fixed rear sight.
I will get pics up later on.
Edit- I think it's an Austrian issue M12 with a military acceptance date of 1916.
It is imperative to strike down the rise of modernism which would lend itself to folly such as the use of billet components.