Under the car you have, for major seams the firewall to main floor, main floor to rear floor and from the main floor to rockers. Typically the only seam that would receive a sealer after the floor color was added (none applied before the color on these seams normally) would have been along the main floor to rocker
Some times when the worker had more time and product he would continue the application along the front edge of the rear torque box (just in front of the rear spring mounting location) and along the inside of the rear frame rail to floor seam for maybe 6-10"
If the firewall to floor seam was a poor fit there would be a wide application applied over the front of the bellhousing area to cover that up
The rest of the firewall to main floor, main floor to rear floor were sealed on the top side in the interior so no reason to repeat that under the car though "restorers" have done this for years and others have often IMHO blindly copied the practice again and again
