My truck has milky oil!

[54belair]

You have two GOOD indicators. One-- You said the engine had "good power" and two--you said the engine still held 45# oil pressure just before you shut it off.

Chances are youre bearings are fine (for an old engine).
If I wanted to keep this engine start out replacing the intake gaskets and yes, the timing chain cover gasket.
With good engine power chances are its not a head gasket . Remove the intake slowly and easily trying not to tear or damage the existing gasket (so you can do a good visual inspection. I would change the timing cover gasket simply because you already know it leaks!

Now--with that said, before I removed anything Id check every bolt for tightness before I loosened them.
You said the PO "started" doing some stuff and didnt finish-----maybe he didnt do what he Did do correctly. Im always skeptical about someone elses project--even if they finish it. Just because he said he did something correctly---doesnt mean it happened that way.

If you get the intake gaskets off and see no indication of leaks, then Id go ahead and pull the heads and replace the head gaskets---once again, get a torque wrench and check head bolt tightness Before you break them loose.
After you do all that, since you will have the distributor pulled, go ahead and spin the oil pump with a drill motor to make sure everything is prelubed with good oil before you spin the engine again.

Anyway, good luck----this is the procedure Id use on my own engine.