I wouldn't go that far
They could have run some UOAs and got better results with thicker
Could have quieted some engine noise
It may have had low oil pressure
Could be an old timer who swears up and down that "30 weight is no good it's like water in your engine"
Or you could have a high pressure oil pump, or the bypass valve in the pump is stuck closed
Or the secondary bypass valve could be stuck or deleted as part of an AFM thing (not sure if your rig has it)
Oil could have some lucas stuff in it which basically knocks the oil up to the next grade
Engine could have been rebuilt with some tight ass tolerances
There could be an obstruction somewhere after the sending unit, though that would be fairly unlikely IMO
Or for that matter you could have a bad stepper or sending unit
A bad oil filter will NOT cause high pressure as the sending unit is located post filter
Either way. I'd agree that your oil pressure is a bit on the high side. That being said, I wouldn't be overly concerned about it. Even if it is the wrong grade, 1 OCI won't do anything for the longevity of the engine, good or bad. But if you want to get to the bottom of it due to a return window or warranty purpose, I'd say change the oil and contact the previous owner (if you can) and see if there were any engine modifications.
Change your oil if it puts your mind at ease. Oil is cheap
