Thanks for the pictures. It does look to me like someone coated over the whole thing. The faceplate is a good test area. Try alcohol. If it cleans off, you have shellac. IIRC lacquer thinner will dissolve old lacquer. If you can find what the stuff on there is, you may have a chance at cleaning it up without destroying your decals.
Your best bet might be to clean off the plated parts and leave the body of the machine alone.
Rodney