Without taking measurements of bearing fit, you are placed in a position of second guessing what went wrong.

 

I know the first place i'd go back and check.

 

You don't know if it carried any oil pressure before. The truck is 33 years old if it doesn't knock while running then you got pretty close on the bearing(s). You are going to have to pull the pan to work on this anyway buy a $5.00 dollar plastigauge and find out what is going on. A new oil pump isn't all that expensive. Over the years my experience with 385 engines is that either the pump is bad or the cam bearings are are wore out. The 385 motors need a lot of volume.