I store my winter wheel/tires sets like that. I let some air out, but don't really deflate them. Maybe down to 15 or 20 psi. That way in the heat of July the pressure won't go up too high.

Stored tires - the rubber gets harder with age, they'll still work. But the harder rubber can be more slippery sometimes, and they probably won't last as many miles as if you used them 8 years ago. Inspect the sidewalls as you use them - maybe they'll start cracking before you wear them out. I'd get them, but just be aware of all this when you negotiate a price...