The metal handwheel looks like one of Romans' older ones. It is lacking a chromed washer that is supposed to go in-between it and the "gear". If I were you, I would look for that washer if I wasn't sure I didn't have it.
The more yellowed resin parts look like casts of an Icons Obi-Wan ANH. When it was made, it was years before the handwheel, "gear" (booster) and emitter (Derwent balance pipe) were discovered. Looks like a clean cast though. The lengthwise grooves in the Icons are probably more accurate to the variation used for the real prop than the white grenade cast, despite being a replica.