So Larry Stoves did offer to fix it but they said that the stem is compatable with the Rim Guard. Maybe I just got a fluke? Anyways, I ordered new metal stems to fix both sides. Larry Stoves is too far away to take it there.
Quote from their reply e-mail.
"He reminded me that tires/ tire related issues are not covered by warranty, however he did say that if you wanted to bring the tractor or that tire by our shop that we would gladly refill it with Rimguard. The rubber valve stems that are on the Kioti tractors are air and liquid compatible, and meet all industry standards for agricultural use."