Absolutely, you will need the grille to match obviously, go for the 1994-up grille so it will fit your existing 1994 bumper-to-grille filler strip. You'll need the park lamps and corner lenses for the grille you choose. Be sure to get the corner lenses for the correct year and brand (Chevy vs. GMC are different.)
The headlights themselves bolt directly to the core support; since you have the large sealed beam work truck lights you'll need the 4 bolts as well, if you're getting the headlights from a donor truck. 4 bolts each side and the whole bracket holding the lamp buckets comes right off.
The wiring will need to be modified; since you've got a 1994 you could get the whole factory front lamp harness from the 1988-1989 truck and replace your W/T harness with it. It's a little tricky but the front lamp harness separates from the block at the firewall on the driver side. Once you remove the center screw from the block and pull it off the firewall, then you gotta hold your mouth just right while reaching into the black weatherproofing goop with a small screwdriver or pick to release the locking tab, then out it comes.
Barring replacing the harness with the factory piece you'll have to splice in the correct connectors since the high and low beam function are now split between two lamps instead of combined in the single large lamp you used to have.
It should be considered that quad lamps from a donor truck will likely have seized adjusters. A member here was recently posting some excellent info on reviving these without damage; a quick search should pull it up. Here it is - go to post #14 for the solution.
https://www.gmt400.com/threads/88-89-glass-quads-achilles-heel-the-adjusters.56004/
Richard
