The ones youve got look like factory tail lights. The 73/74 ones were square like that.
They're kind of charming if you ask me.. I like to think of them as a very early version of the now-ubiquitous tail light housing. Somewhat primitive, sure, but they are good evidence of the many forces driving the change from individual lenses mounted to the tub structure toward a dedicated taillight housing assembly that had them all attached to it.
Also, follow this link to find the master parts list for all LUVs:
http://www.luvtruck.com/Information.htm. That will tell you for sure what you've got and what you're missing.
I'm not aware of a valence for the rear end, and I don't think it's shown in there either.