Excuse my ignorance, but why does it matter? Most tire shops/warehouses I've been to are inside and out of UV exposure which is the biggest killer to tires -surrounded by thousands of other tires. If they are 6 mos or 12 mos old, who cares? The lifecycle should pretty much start when you put them on your coach - when they start getting exposed to elements and sun. Whenever I got new tires for a previous MH's I never even bothered to look at the dates. Inspect them every year and knowing I will replace in 6-7 years from when I bought them. Never had an issue. Sorry, I don't get the fuss. If you buy an RV off the lot - a leftover 2019 with 2018 or older tires, do you replace those tires at 5 years or 7?