My opinion, which there are many other who are much more knowledgable than me on these forums, but to me, it all depends on what you want to do. personally if i was going through the trouble of Swapping an engine, i would replace all 32 lifters/ lash adjusters, change the oil pump for one with a Bronze gear or hardened gear set ( around 300$), new main and rod bearings, while the rotating assembly is out put a little more cross hatch back in the cylinder walls with a simple quick ball hone, ( probably wont even need it from what ive heard/seen about these engines as they always seem to have cross-hatch still, even with high miles), then id do The valve cover gaskets, oil filter adapter gasket, and new rockers while your doing the lifter so you dont get irregular wear patterns on your new lifters from re-using the same rockers. All in all , im just basically saying i would do the above, and then also
1. re-ring/ re- bearing
2. Oil Pump
3. Lifters/ Lash Adjusters
4. Rockers
5. Updated Timing assembly with better updated Primary Timing Tensioners ( MMR Sells These)
with all this you would basically have a brand new engine, it just all depends on what your budjet/ goals are. Personally, i think if i was going through all the trouble of swapping an engine i wouldnt want to have to do it again eventually, but these engineis are great and extremely reliable even in completley original form and so some of what i said may or may not be nescesarry/ important to you.
Just food for thought