Unless I'm mistaken,, all OM g/f's were an alloy except for the Super Blackhawk & the Old Army. A NM steel g/f will require the use of an adapter block for the trigger return spring. A common conversion,, often done quite easily.
There were, indeed, a few OM XR3RED steel grip frames made for the Old Army which would match the original aluminum XR3REDs. You may find one here . . . good luck.