After 15 years both my headlight lenses had serious clouding and one was taking on a lot of water. Rather than trying to restore them I bit the bullet and bought replacements. Iron Horse RV in San Antonio recommended Certifit.com and I ordered a pair from them. Ford wants >$300 apiece for the modules while these came out to less than half that with shipping.
The units seemed well made and the tech who installed them said they appeared to be virtually identical to the Ford ones. The only difference appeared to be the connectors which were all different from those used on the Beaver but were easily changed. Some milling/cutting was required but Gerald had already warned me that would be necessary.
All in all, the new lights are a very nice cosmetic improvement to the coach and I'm sure the nighttime performance will be a lot better, even though we rarely drive after dark!