Yes, those are split-type rims with tubes. Another way to tell is to look at the inside of the rim, behind the flange where the lug bolts attach the wheel to the hub. If it's a classic multi-piece rim, that area will be straight, with no drop-center for the tire bead to go into while mounting the tire on the rim. A lot of the older trucks have brake drums big enough that a drop-center rim won't fit over the drum unless you go to a much larger tire size, like replacing a 16" tube-type wheel with a 17.5" tubeless tire.
There's nothing wrong with those wheel studs. Give the rusty section a good shot of PB blaster or Liquid Wrench and spin the nuts on and off a few times. They're not deteriorated enough to weaken them at all.
Find a good big-truck tire shop, and they'll probably work on those rims with no complaints. If there's a farmers' Co-Op with a tire shop in your area, they are probably accustomed to working with split rims as a matter of routine. It's the big-city tire shop wimps who have to sit down to pee who get all flustered about sectional rims. Us farm boys and/or big-truck guys don't have a problem with real truck tires!
Jerry
