This is incorrect.

The tag on the door jamb is the tire pressure required to achieve the axle rating stated on that same tag. There are a variety of tags out there so it can get confusing. E rated tires can accept up to 80 psi (or whatever it says on the sidewall of your particular tire if you are running something different).

For LT265 tires, it breaks down like this:
4670 lbs on the axle requires 50 psi minimum.
5200 lbs on the axle requires 55 psi minimum.
6084 lbs on the axle requires 70 psi minimum.
6830 lbs on the axle requires 80 psi minimum.

This is as high as you can go with LT265/75-R16E tires so there no SRW trucks with axle ratings higher than 6830 lbs.

If you are running LT235/85-R16E tires, the figures look like this:
4400 lbs on the axle requires 60 psi minimum
5200 lbs on the axle requires 65 psi minimum
6084 lbs on the axle requires 80 psi minimum

A 4x4 CrewCab short bed PSD has about 4620-4680 lbs of weight on the front axle so you need at least 65 psi for LT235 tires or 50 psi for LT265 tires up front.

The rear axle is much lighter when unloaded, around 3300 lbs or so. So, you can run lower pressures back there and still be safe. At that point, most people try to air up the tires so the tread lays flat and doesn't cup in the center. You can use some child's sidewalk chalk and draw a line across your treads and then roll forward and see where the chalk rubs off.