G-Y Eagle ST age?

I'm looking at buying a set of 215/70-14, Goodyear Eagle ST tires, to run on stock, 14 x 5.5" Rallye wheels.

I remember seeing these tires quite a bit on cars in the 80's and 90's, but haven't ran across them in years. Anyone have an idea on how old these might be? The guys selling them says they're no more than 5 years old.