here is the info on what the light fixture is.
1973-1986 GM pickup bed light
GM Part #5969836 Lens i bought new ones for my 90 on ebay for 9 bucks apiece. you just gotta look for them. i made the foam gasket out of window/door foam seal.
Housing, #5965873
you can buy led bulbs to go in them. so a couple of things to keep in mind.
1. will the bulb fit. the more led's it has the bigger it is.
2. the lens is often yellowed. it will take a way from the bulb brightness
i am not sure how long newell used them. alot of bus converters used these for quite a while. so not sure what year newell changed to something else.
