yes, something like that. i took the "seal" from a can of MonsterDrink, some kind of tough but thin material that's fairly good sized; cut two parallel edges on it, and i've inserted those into some marginal sheaths... left a little bit out as well. aids retension and sound/rattling in one go. for the BK11 sheaths, i might even put some adhesive on one side.
the heat/squeeze worked well with the original Camillus kydex sheaths. not sure what you're going to get with the new ones (as they are glass filled plastic?)
perhaps one could drill out the rivets, and line the sheath with either plastic, or some kind of leather? reassemble with rivets or screws (esp if you are using a TekLok)... the right kind of screws with the right thickness of liner would allow some adjustment on tension as well.
Bladite