Looks like a clone of an early OS Max I. Likely an Eastern Bloc country, but anything is possible. The Russians made clones of Fox .35 Stunts; probably threw in free burps! If the screws are original, a fair amount of evidence is available there...often custom made, always slot head, etc, usually very crappy. Anywhere else, they'd buy the screws.
My first (early) DS .60bb had this sort of screw. The threads in the case were beautiful, but the screws sucked bigtime.
Steve