Sounds as though you've pretty well answered the question. I have several 60's products, and all have plastic handles. I also have one of the first second generation Model T's, and it has leather handles. It's vintage 1974 or thereabouts. The mid select switch hadn't even appeared in the catalog, and it doesn't have the red knobs. The guitarist in my band ordered a Model T based on the first generation amp, and this is what he got.