Don't know if Avon used hypalon in their life rats. If they did it would be good for quite some time like decades if stored well. If left in the cockpit
like we did with ours, it will be toast and worthless. Without a recertification, i wouldn't pay a nickel for it. At the least I'd inflate it and let set for 24 hours to see if it still holds air and remove the CO2 container and weigh it to be sure it's full or better yet have it refilled and repack it myself. Testing, repacking, and recertifyinbg by a professional will probably cost more than a 'boat unit' which makes buying
a used raft a gamble with odds that would make a Las Vegas slot machine smile.
Avon was bought a decade or so ago by zodiac
, brought down to zodiac's quality level, and eventually closed down. Doubt you'll have any luck finding anyone home at Avon. headquarters.