Not unusual Tom. Probably attributable to the bearings being
worn some. If you ever have a need to pull the pan down it wouldn't
hurt none to reshim them. Might bring up the pressure a bit.
Don't cost that much to pull the cover off the oil pump and see
if the gears are worn or if the bottom of the housing is
showing any wear. Really a simple pump and you can get
rebuiling kits for them. It's also possible that someone put a
homemade gasket under the cover which would lower the output
due to to much clearance (pressure leakage) at the ends of the
gears.
Denny G

Denny G
Sandwich, IL