I think you may have the F.N Mauser Modelo 1935 with an 18" barrel with the reversed wing safety.
When you engage the safety catch you rotate it to your left, the exact opposite of all other Mauser rifles. They did it, for the "marksman" in both the Army and the Police at thew time, so they could move their cheekbone further forward.................not sure whether that helped mounted troops or not as they took a shot, bouncing around on a horse!!! FN vertially disowned the production, but it was a hell of a rifle, and admired by many Firearms manufacturers in Birmingham UKicon including Parker Hale.
I'll rack my brains here and say probably the only people your side of the pond who could fulfil your wishes are Numrich Gun Parts, I remember he had a great interest in the short 35's at one time.

Drop them an email: Gun Parts & Firearm Accessories | Numrich Gun Parts
and let us know how you got on.