BTW, I have found Impala Bench Seat Trim to be the same on 2-Door and 4-Door cars. The 4-Door Trim has the same "Split" just like a 2-Door Seat has and has 4-Separate Pieces total per Seat, like a 2-Door Seat has.
Not only have I compared them all through the years, I have sold countless sets of 4-Door Seat Trim to 2-Door owners and no one has complained yet, lol.
Also, both '63 and '64 Trim is also the same.