Hy Jhbabb, welcome, nice truck you have there, your son must be pretty nice too to give you such a gift! Unfortunately I'm 90% sure at least your front wheel is an RH5 widowmaker, they are outlawed, no tire shop will work on them and they shouldn't they are extremely dangerous. There are limited replacements available, the most common would be tube type multi piece wheels. That type of wheel has had two different wheel center hole dimensions and I'm not sure when they changed to the larger size, so measure your wheels center hole and your axle hub to make sure of the dimension. Tubeless wheels became the factory standard in 1956, unfortunately a lot of truck buyers didn't trust these new fangled "tubeless" tires and they paid extra to get multi piece wheels and tube type tires, so those tubeless wheels are very rare and expensive if you do find some. Your wheels are hub pilot Kelsey wheels. There are some modern tubeless wheels with the bolt pattern, ten holes on a 7 1/4" bolt circle, unfortunately they are only 19.5" wheels not the 22.5" that the factory put on the trucks, most of us consider the 19.5" wheels to look too small on the trucks. There is a Tech Tip on wheels here and you should read it to become acquainted with the subject of wheels and tires, good luck with your search.
