timeking,
CapriRacer is right..
a P assenger tire is usually 35psi; they can go higher, but mostly for a lower profile, higher performance/speed rate/etc..
an LT light truck will be from a load range C/D/E, and this corellates to ply; which then increases psi, and then weight, and heat dissipation, etc...
skip whatever the placard in the door jamb says.. this is what it was manufactured with whenever.. just like computers, tyres become antiquated in 6months.. they still work,
but that data plate is stipulating what your rig came with, whether for 89yr old grandma that takes her truck to church on sundays, or the teenager; ricky racin' and bo&luke dukin' out in the bayou..
if you are concerned with high payload weight, over highway surface (mostly), higher mileage than 25,000 and throwaway treads, and not a huge sacrifice on mpg as well;
get the tires you want/prefer/size in and know that the psi stamped on side of that tire is what that manufacturer has tested to max, and will meet or exceed the OEM ones that were inadequate before they were mounted.
here is a rundown of what i think you are looking for:
https://www.treadwright.com/blogs/tr...-vs-load-range