They could very well be two piece rims. There is no doubt that they are tube type rims. There is one way to tell easily on that type of rim if it is split. There is a lip on the outermost edge, from there it recesses toward the inside of the rim and meets the next lip. Scrape the paint off where that recess meets the next raised rim. If it is one piece, the metal will be smooth in the transition to the lip. If it is split, there will be a valley or obvious joint.
For the wheel studs, you can drive them out with a hammer, a brass drift or a press. Insert the new studs in from the back, spin a lug nut on, tighten it down and it will draw the new stud into the hub.
