old ornate gothic cast metal hardware, large decorative faux hinges

Three large cast metal 'appliques' to look like castle gate or door hinges - these are flat metal pieces about 12" long. They'd work nicely behind door knobs or latches too, or as brackets behind sconce lighting (lamps or candles) or behind hooks. They have a black iron look finish, but are cast zinc or aluminum, we think? The painted finish has some wear and pitting.