Good For You... What is the Serial Number of that gun??? I Have both forearms in my hands now. I think that your forearm is correct as the Super 10 has a different latch, also the engraving on your forearm matches the magnum forearms that I have... However my suppers are all graded guns, and the Mags are all Field grade guns. The gun was built for big loads, even the supers will shoot heavy loads.
David