[Arran]

The grille cloth is wrong, and the knobs look like those used on a U.S made G.E, originals would have been either rosette knobs on a model 50, or the older flower pot style if it were a model 21, there is also some cabinet damage, and someone had a go at refinishing at least part of the cabinet, it's all academic anyhow since neither a model 21 or a 50 is worth anywhere near $500. People generally buy these sets because they like the cabinet, and there are more then enough model 70s around to fill that need, which was a better set then either the model 21 or the 50. What would tell the tale if it were a legitimate factory set, would be if we could see the plywood bottom, preferably from the inside with the chassis removed, if the factory had re-drilled the bottom the holes for the model 50 chassis would have been countersunk from the top for the chassis washers, though I think from the pictures we could say that there are no recesses for chassis washers. I had an opportunity to buy a model 51 about three years ago, the price was O.K but not great, but I think two of the knobs were missing, or wrong, and rather then go on another parts hunt I just walked away, I don't think the model 51 was much better of a design then a model 50.
Happy Christmas
Arran