THANKS for the fine detective work
I only have a 78-81 parts book and this part is not in there. They show a metal plate for those years.
Also, I searched the whole internet, doens't anyone make clutch rod boots for trucks? in my 79-81 book it shows part number 3732938. Only place I could find that number is on one of those military surplus websites (they dont have any but they had the number). Said that number superceded 2830873. This hole plug and those part numbers are different than the one that fits all the 66-76 cars - that boot number is 2266783.