as i stated, my full coupe pan does not have these holes. they may have relocated your shaker hole more forward or it maybe a hole for the dynacorn production run but its definitely not on mine! the only diff. is my pan is a 67/8 pan and yours is a 69. they install a fixture where this hole is to set the gap between the trunk and upper rear cowl panel to get the foundation on the bodies straight.

it looks like you are replacing the whole rear of the car. do you have more pictures of it and have you done this before? im doing this to my coupe but have not completely cut things apart as i have no one to consult on the process. i need full rear trunk pan, both quarters and all wheelhouses replaced. i've considered cutting it apart and replacing the rails at the same time for ease but if i do i have to have someone to talk to on this as i know nobody who can do this to its extent!