Look at the manufacturing date on the sticker on the driver's side doorjamb. In mid 1993, Ford changed the Explorers to include both EGR and R134 refrigerant. My 1993 was manufactured in February 1993, and is one of the earlier models, no EGR and R-12 refrigerant.
In short, if you have R-12 refrigerant, you have no EGR.