The core support will only be between 73-80, 81+ is different. Within the 73-80 range I don't know if they will all actually interchange or not. Sometimes you have minor differences that dictate new part numbers but in reality the parts interchange. I have an old body parts book but it only goes back to 78 so I don't have any info on previous years. On the 78-80 core support, it was serviced as an assembly by GM, no pieces.
With respect to the hood latch style, inside vs outside release is option related not by year. This means 2 trucks the same year model could have each type.