I have a bent front wheel hub cap and I've been looking for replacements. The company that made mine has stopped making them. I tried all the RV Salvage Yards... no luck there.
Lichtsinn RV had some replacement hub caps but you had to purchase all 4 wheels.
Folks have told me to visit a big truck stop because many have tire shops. In fact that "Worlds Larget Truck Stop" gets a lot of recommendations. But I've not been to Interstate 80 in Iowa to see.