The driver seat left front mounting hole is 6 inches from the side edge of the raised seat platform part of the floor and 1 1/2 inches from the front. The driver seat right mounting hole is 14 inches from the center of the left hole. You should be able to determine the rear holes by using the seat tracks. The passenger seat right front mounting hole is 6 inches from the right edge of the floor and 11 5/8 inches from the back edge of the raised platform part of the floor. The 2nd right front mounting hole is 1 3/4 inches directly in front of the first hole. The passenger seat left front (1st) mounting hole is up on the tunnel and is 2 3/4 inches from the right edge of the tunnel. The (2nd) left front hole is 1 3/4 inches behind the first hole. Use the existing seat mount brackets as a guide. The 2 passenger seat bracket holes are 16 1/4 inches apart.
My original floor was replaced by the PO, so this is assuming he re-drilled in the correct places.