Tobins are neither true sidelock nor boxlock. Kinda a hybrid action but look more like a sidelock. They never made a boxlock. Their value in my mind is their relationship to Canadiana. The stocks are pretty droppy but I can shoot them. If it is in “excellent” condition, it would be rare. Most were working guns and were well used. An “excellent” example, even if it a basic model, might be $600ish. Maybe more to a collector.
I’d love to see a picture.