It would be a good idea if it hasn't been adjusted in years. I just did mine (I checked them several months ago, and they started to rattle so I tightened em up last week). It might help with power, but just a little tiny itty bitty smidgen. You might want to check all the basic stuff, get some spark plugs, cap rotor, adjust timing idle, etc. All that can make a tremendous difference.
'89 Pickup 2.6 4wd 2.3 head, Weber 38, Pacesetter header, Flowmaster 40, MSD Blaster coil, ball joint flip, 31's, Per-Lux fogs
'80 LUV aka "The Luv Machine" 1.8 4wd 3" body lift, 2" susp. lift, 31's, Weber 32/36 DGV