Mike,
The OEM Ford lights will need to be modified to fit your coach, and you should carefully seal the top seam on the headlight after modification to prevent water from leaking into the headlight.
What problem are you trying to repair by replacing the headlights? The vast majority of owners can not tell the difference in OEM or aftermarket headlights If they are providing poor road lighting, new headlights will not repair your problem. If you have a lighting problem, you need to install relays and/or high output blubs in your headlight system.
Gerald