[klhansen]

I believe the higher capacity 17 degree pump was on the 99.5 models which went to slightly more injector capacity over the early 99's.

Also front covers are not easlly interchangeable between OBS and Superduty engines. A major difference is the location of the pickup tube changed sides. Passenger side on Superduty front covers.

 

[klhansen]

Thinking you can get a high capacity aftermarket 95 HPOP from some vendors though… please correct if I’m mistaken, without having to retrofit front engine cover.

I don't think there are any problems with bolting a later model HPOP on an OBS engine.
There were a few front cover changes during the 99-03 7.3Ls, one being a change to add an inlet screen in the HPOP reservoir as part of the gasket. The front cover was modified to fit the gasket with screen.