Mounting Jumpseats: 74-78 vs. 79-84?

[DirtyLawyer]

I have a NZ market 1982 BJ42. It came with the long bench seats, thus no roll bar. looking to put in a roll bar, therefore changing out the seats.

Question: would it make a difference if I used the 74-48 seats vs. 79-84 seats? I have a really nice pair of 74-78 seats, but they will require drilling the wheel wells to mount. Would I have to drill to install the 79-84 seats as well? There are two drilled/threaded holes on each wheel well, would those fit 79-84 seats perfectly without having to drill? Hoping someone knows the answer.

I've attached a pic of the involved area.

Thanks