Welcome. If it were me, I would closely inspect inside and outside sidewalls for dry checking (little lightning bolt splits). Do the same for each groove. Yes it will take physically getting on your back with a flashlight. If the tires have been kept covered, and hot parked on concrete or gravel without a rubber pad, they can last much longer than 5 years. There will probably be many of the Forum “ engineers” who will disagree. However, if you can negotiate new tires thrown in, go for it.
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