Should I be concerned with airing up to 80 psi on these rims?
Yes...never overpressure a tire or a wheel. You have the wheels so look for a load and pressure rating or check with the wheel/trailer mfg. Some of the better 15" quality aluminum wheel mfg say the valve stem determines their wheel pressures up to 80 psi.
If the wheel shows a 2830+ lb load rating then its good for 80 psi.
If it shows a 2540 lb load rating its good for up to 65 psi.
Carlisle HD and Goodyear Endurance both are to be ran at max sidewall pressures.
Carlisle says to use max as part of the new tire warranty.
According to Endurance owners the tire is stamped on the sidewall "inflate to xx psi".
Check out the Providers. They come OEM on some mfg rv trailers now and have been OEM on commercial trailers since the '10-'11 era.