No point on putting it on since my low oil pressure warning a few months back was due to the bearings being eaten up by coolant in the oil.
I think you'll want to verify oil pressure before condemning the engine and going through more work than you have to.
If the engine runs fine, no noise, decent power-- it probably has some life in it.
I recently rehabbed a 3100 V6 that was seriously overheated to the tune of bad head gaskets, milky white oil and likely run that way for quite some time. I couldn't tell if there was any metal in the oil because it was all white, I just knew it was a runner as is, so I figured it would run fine after. Couple reman heads and a few hours of my time later, the engine is as solid as a rock. You'd be surprised the abuse these old pushrod engines can take and keep going. Especially the all-iron 3800.