There are differences between South African cars and Mexican cars. The bolt on birdcage tubes either side of trunk are so a one piece glass trunk can be installed. Cowl brace tubes bolt in so footboxes can be removed and installed.
Oil cooler brackets bolt on so glass body can be put on over nose. Some front bumper brace tubes bolt to the front of the frame rails for the same reasons. Need pictures or details of something specific let me know.