Back then, they didn't have super adhesives for metal? At least not that I'm aware of. I would think soft soldered, and rust blue touch up. Ooooorrrr, silver solder and total frame re-blue, rust or salt...
My guess for now, epoxy should hold it on tight and square, just no sharp knocks, the epoxy will part clean! Just like it was intended to part like it was molded smooth!
... best, til...lat'r.....GT
