Bigsky,
As has been stated, the "true" way of knowing what kind of EXACT tire pressure you need to run in both the rear AND THE FRONT is to take the time and, run down to your local scales, could be a van and moving storage place, could be at a recycle place or, truck scales etc. But, get both the front and rear weights of the coach.
Then, come home and, look up your make and model of tires and, find that brands tire inflation chart on the net. Find your exact size and model of tire (there are sometimes many versions of the same size tires on certain brands site) and, see what they tell you to inflate your tires at.
That is the only true way of doing it. The plate that comes in the coach is a generic plate that covers only the basics. It really does not take into account what kind of weight you're running, on either axle. There's no sense in running over pressure if your tire chart tells you to run something under what's labeled on that plate/I.D. in your coach.
On the other hand, your tire chart for your particular tires may tell you to run quite a bit higher than what's stated on the plate in your coach. Good luck.
Scott
Scott and Karla SDFD RETIRED2004 Itasca Horizon, 36GD Slate Blue 330 CAT
2011 GMC Sierra 1500 Ext Cab 4x4 Toad
2008 Caliente Red LVL II GL 1800 Goldwing KI60ND