New England Custom Guns replaced the fore-end including the iron on one of my Greifelt drillings, and all of the screws which some idiot had lost from my JP Sauer und Sohn pre-War Anson-Kerner 12 gauge side-by-side. I would at least let them look at your gun and give you an estimate.

Incidentally, the 6.5X52R (.25-35 Winchester) should make a hell of a deer cartridge.

Can you post pictures of your combination gun?