I wouldn't drink New, Old Stock coffee, either.
Sure it may be brown and hot and full o' caffene..but i'll take a fresh can of Tasters Choice over something I picked out of a 20 year old MRE anyday.
Altho MRE fruit coctail is always good.
8 Ply is on the higher scale of tube type tire but my biggest concern would be the age of the rubber.. would it be as bad as one of those old 'No Hunting' fencepost tires? Of course not.. but would it retain the same degree of strength and elasticity after 20 years of storage? I wouldn't think so.
What you have to consider is what happens to a tire on a molecular level over time.. stuff you can't see from a visual inspection, and what those effects will have when you exert the kind of force on it that it takes to get it on a rim, and zip down the highway at 55mph with three or four thousand pounds of steel riding on it.
