Floorpan questions on 75

[eighteenninetytwo]

I took my front seat out this weekend to prep the inside for cleaning and painting etc. It turned out the bench seat was only bolted down at the front on the passenger side, and there were no corresponding holes at the rear of the seat. The passenger's side appears to have a triangular bolt pattern in the floor. I'm planning on fitting two individual low back seats so is this the correct floorpan and bolt hole pattern for a 75. IF it is NOT, what year seats fit this bolt pattern if any??