I always assumed the "age" was more of a guesstimate. Which is fine, IMO. I don’t assume warranty services when looking at used gear.
I’ve bought from TMR several times. Always got quality gear. There is ONE time I got a set of Tannoys that were internally wired wrong (Tannoy uses no-solder wire clips), and sounded absolutely horrible until I rewired them (very easy to do). Fortunately I knew what they were supposed to sound like, because in the meantime TMR customer service tried to convince me it was an amp matching problem lol (I hadn’t discovered the wiring mistake yet). But once rectified, those ended up being one of the better bargains I’ve gotten. So once in a while their "testing" may be a little lax, but otherwise I’ve been very happy with TMR.