hmm the 3rd brake light is the best part about the NAS 90s ...clearly you should just give your truck to me!
In all seriousness, are you talking about the entire bar assembly? or just a bracket at the top of the bar to mount the light?
If the bar is what you need i believe someone here on the forum makes a very high quality replica.
The light is going to be MUCH harder (impossible) to get. They are about as rare as parts come for NAS ST defenders. There are old corvette 3rd brake lights that are similar. My vote is for a hella 3rd brake light.
I just installed one this past week and its great. LED lit and very high quality... not to mention brand new.
Again you should just get rid of your WORTHLESS truck and give it to me... that is the least painful route