While I have never aged a bone-in sub-primal myself for the reasons I will soon explain I don’t see why it couldn’t be done whether it is concave or not. If you use the proper size Drybag then there should be sufficient material that will draw down to form the skin during the vacuuming process. Now the reason the bone-in doesn’t appeal to me is I don’t have a butcher saw to saw through the bones to make individual steaks. Even if I were to simply trim the bone off after aging it seems to me that the meat against the bone will not have lost much if any moisture resulting in a layered steak of an aged edge and unaged. This is just my opinion though!