It depends on the budget you have, how much you can do yourself, and time restraints. If none of these apply then yes do a complete rebuild, and think about a performance based rebuild, i.e., bigger cyls. upgrading the cam, and maybe enlarging the valves. Or if on a limited budget, opt for just enlarging the cyls, the larger pistons wont cost anymore, jut the labor to bore the cyls. If you are limited by all 3 than just get the head inspected, replace any of the valves, and replace the HG.

More than tread lightly. Leave it like you were never there, nor anyone else.
'90 X-cab 4.88's 33 BFG AT's, rr ARB, Headers, Ignition upgrade, cold air induction.
'91 X-cab 5.29's 315's BFG MT's, rr ARB, custom bumper and flatbed