Hy Jim Sears, yes they do exist, I have a set on a 1956 15 series. In 1956 GM converted their whole production even Chevy trucks to tubeless tires. Needless to say many people didn't trust the idea of tubeless tires on their trucks so they paid the extra cost to have their trucks outfitted with tube type tires and multi-piece wheels, that is why the tubeless wheels are so rare, hope that helps.