Was an exterior hood release offered on the '81+ trucks, I don't think I've ever seen one. My '80 had one and I liked the rock solid reliability of it, my interior hood release cable has always made me nervous.
Was interior always an option? My 78 has an interior release?
The old farmer I bought my Jimmy from had gotten tired of using the standard hood release lever in the cab, so he bent a small wire around the hood latch and made a loop on the end. If you knew where to look, you could stick your finger in the grill, pull the loop, and the hood would pop open.Would be pretty simple to make happen with a cable and lever inside there.
My 88 K5 has one, when I bought the Blazer it was broken & I couldn’t get hood open without a screwdriver. I put a new one in & it still doesn’t work good, I’ve realigned hood closure, but probably needs more adjustment.