Am I right in thinking that these tires, which are very good examples of '70's or early '80's' 4-ply polyester bias ply tires, still have a lot of miles in them? Like 4000 or so? They have almost-new tread, and the sidewalls are, to me, quite acceptable. They are Cooper "Untouchables" by name.

I want to keep them, but will also listen carefully to contrary (or supportive) arguments/suggestions.