Hello,
so, to my opinion, this is not the case, this scope they did for the E11 in ROTJ is the prop makers take on reproducing a M19 tank scope from scratch.
The to best refs I have to show that are those:
The back part is very clearly the bell from a scope cut down, from which scope, I don't know. I think thd9791 has come close to find a good scope in the wild with close dimenssions but there is no definitive model for this scope bell yet.
the front part, to me is a just a basic thin metal cap from a perfume bottle, or water bottle or i don't know what, I'm hoping to find one one day, They just riveted it on the cut scope. No on is offering a replica that comes close to this, they always machine the cap from aluminium when the real one is really thin.
and the front part is a mix of two parts, one the adjustment bell of a vintage scope, exactly the same as found on the Boba feet scope and the very front part, I don't know, probbaly a small found part too.
I'm absolutelly sure the whole scope is not from one real scope. it's a mix of at least 4 parts and a rivet.
cheers