The only thing that will work from one to another, is the turn signals, They will work with the 91-92 headlights and the 93-94 headlights, grilles have to stay to the year of the headlights, and just to let you know, if you have a 91-92 and are intending to get a 93-94 headlight set, the wiring ends to the lighbulbs are different as well.
Been there done that.