We replaced the rectangular Bargman's (apologies for the dirty Scamp
in that photo!) with the Bargman 07's. Two of the holes from the old lights lined up with the new lights, one was hidden under the new fixture and one we plugged with butyl tape.
The new lights DO have a license
plate holder although we had to get slightly longer bolts. There are no backup lights but we decided that wasn't as important as brighter taillights for going forward!
The part of the unit that houses the lights IS sealed. The lens does come off.
It is really nice to have brighter taillights!
Fran in NM