Gary,
I have a 1995 truck and a (wrecked) 2000 truck. I have swapped the hub caps back and forth between them. This has been with the 1995 factory chrome plated steel wheels, the 2000 factory aluminum wheels, and 19. 5" Rickson steel wheels.
Everything has fit, but sometimes the caps are a bit loose. In my case, I cut some pieces of foam rubber to jam inside the caps to prevent them from rattling.
The hub caps attach to the lug nuts, and I'm pretty sure that the aluminum wheels have different nuts than the chrome plated steel wheels. I suspect that's why I needed the foam to tighten everything up.
I've never lost one.
Good luck,
Loren