Tail Light question

[nmrockcrawler]

I am in the process of building a 79 Scout II that I purchased several months back and have been going through and fixing p.o ( previous owner) interesting fixes... One of the issues I am wanting to address is the tail lights. With the Scout I acquired a bunch of parts, two such parts being a set of tail lights that are metal and the ones on the Scout are plastic and busted. I would like to switch them out but in looking at the wiring they aren't even close to being the same. Will this work? Or am I barking up the wrong tree?
Thanks in advance

 

[FDChappie]

On the '79 the plastic ones are original. My '74 was switched from the metal ones to plastic due to the lenses being faded on the metal ones. With a bit of silicone grease on the connectors the plastic lights do a good job of keeping the water out and the bulbs and sockets last longer. If it were mine I'd replace the plastic lights.

 

[Scoutboy74]

The main difference between the two styles (other than materials) is how they receive negative ground. The early metal design relies on sheet metal contact, which means one less wire in the loom. The later plastic version requires a separate ground wire run to a rear chassis ground location. The remaining wires are essentially the same between the two styles. You have one hot wire for the taillights, one hot wire when trans is in reverse, and one hot wire for brakes and turn signals. Perhaps the pigtail couplers are different, but either can be bypassed to adapt from one design to the other as long as the circuits are properly identified and well connected.