Ok, maybe I posted my question too quickely : on the boost mailing list, they answered : no. But even if it was possible, it's not a sustainable manner to handle rollback and compatibility.
Indeed, even if my class T remains the same over program versions, maybe a member U of T will change : so I'll have to check all the members, and their members... versions : arf !!
Finally, we handle the issue with a program ("compatibility_checker") compiled with each version of the program : its purpose is to try loading an archive, to check the compatibility. Sometimes it's quite long, but at least, it's easy : when I rollback from 10 to 5, I check if an archive created in version 10 can be loaded in the "compatibility_checker"V5 and it tells to me if the rollback can be performed with those data.