Rich, I see what you mean about the wax backing you're talking about. Sounds like an old school method similar to dry mounting.
JCM's description is open to interpretation. It sounded to me like he could tell there was some sort of restoration (aka traditional conservation/preservation). It seems you interpreted as some work was performed on it - nothing other than removing some substance off the back of it.
Regarding your comment about how gel resized posters can not be rolled - that is inaccurate. I've had the process completed on some of the heaviest stock posters - the least easily rolled, and after the gel resizing, they were able to be rolled. Although John at PM and Mario at Lumiere recommended to ship, store, etc. the posters flat, they both said they can be rolled. The 40x60 of mine that Lumiere did was less rigid than the one PM did, and it fit in a standard tube (for 40x60s) when I sent a few of them out for consignment.