Order up the dually valve set. I would be extremely concerned if rubber stems are installed on a load E 80psi tire. Blowout is quickly on the horizon. I too have heard of hybrid rubbers that can take higher pressures but metal is cheap an simple to install 453 an 625 grommets are available too. There is a torque spec which is to not over squish the rubber. Usually if you buy a new stem both grommets are included this is also the case if you spring for the dually valve kit
I don't know what it is with tire companies but if it's metal or tpms don't know don't touch or heaven forbid replace with rubber. There are good ones out there but they are rare. I bought my own machine for tires out of pure distrust of incompetent tire shops