I would trust the printing on the sidewall of the tire first.
This could be dangerous. As I said in my example, my rims that came with my RV are only rated for 65 PSI max. My tires can be inflated far beyond that and must be to achieve the full E rating. So I run at 60 PSI and am not getting the full rating.
Load rating D tires could have a load rating of 1,220 pounds at 65 PSI, Load rating E tires could have a load rating of 1,520 at 80 PSI.
I'm running Firestone Transforce HT LT215/85R16 tires that are load rated E at maximum PSI (80 PSI). But my rims are only good for 65. So the tires are de-rated when run at a lower PSI. AT 80 PSI, my tire has a load rating of 2,680 pounds.
Sadly it is hard to get the derating information from the manufacturer. So I just have to hope that at 65 PSI my E-rated tires perform at least at D rating.
Steve