Hi Rob,
I dont see any reason why you couldnt run these tubz on any type of bed (fleet or step) or year of truck. I mean with the fiberglass being so amiable to modification the sky is the limit really. Step side beds are completely flat on the inside except for a couple bullets impressed in the them but that could be easily filled.
I wish I would have seen these before I custom built my own steel wheel tubs!!! these would have worked great for my big PHAT tires!!!!
I would open up your sales to all truck models....