The rims look like what was standard for trucks of that era. Many tire dealers refuse to change tube type 2 or 3 piece rims because they are afraid of them. If a person makes sure the lock ring is seated there is no danger. I usually put a few pounds of air in them and then tap them with a hammer. Then put it in a cage and use a clip on chuck. The danger is inflating a tire with a lock ring not properly seated. Once they are inflated, there is no danger. Let an older experienced person change them who knows what to look for. If they are the split rim type, which I have never seen on that year chev, I would replace them. They split in the middle and there is no way to see if they are seated correctly. If they have a 2 or 3 piece lock ring, that is what I ran on all of my over the road semis until I started switching to tubeless about 25 years ago.