I recently replaced the Bargman type 84 tail light assemblies on our 1987 34W (Bargman part number 47-84-008). These tail light assemblies are used on 1986 thru 1989 non-basement models. Bargman has individual replacement modules for the basement models.
I replaced the turn/brake lights as well as the reverse lights, but only the brake/turn lights are LED. I stayed with new incandescent reverse lights; didn't feel like spending the cash for LED lights that don't get used much.
Here is a link to the Bargman site that shows the lights I ordered:
Bargman tail lights
I ordered mine from Jet.com. They had the best deal that I could find:
Bargman lights from Jet.com
The lights were very easy to replace. I unscrewed the existing fixtures from the base on the trailer and inspected the wiring behind. I decided that there was enough slack in the wires to allow letting the existing fixtures hang down loose while I transfered one wire at a time to the new fixtures. All I needed was a square-drive screwdriver to remove the existing fixtures, a cutter/crimper/stripper tool that is used with crimp-on splices, and a half dozen or so crimp-on splices (red or blue work OK).
Also needed a sharp pocket knife (or utility knife) and a drill.... I used T-nuts and associated screws to remount the new fixtures rather than reusing the original screws because at least three of the existing screw holes in the bases were stripped. I needed the sharp knife to trim some of the base to allow the T-nuts to align properly with the holes in the base, and I needed the drill to enlarge those holes in the base for the new screws.
It was easy to transfer the existing wires over to the new fixtures, one by one. I used dielectric grease on all of the connections, including the ground that attaches to the body of the trailer. Once I finished all of the splices, I bundled up the wires nicely with wire ties.