I'm still adjusting to the front office of the Malibu. Fortunately the previous owner did the seat rail extension STC, adding 3" of legroom. I still have no recline though.

A seat from a -350P is available from BAS. If it will fit my '87 model, I might be up for making the swap.

If I were you, I would call somebody like Kevin Mead who knows these airframes inside and out. He will likely be able to tell you right off the top of his head whether the seats are interchangeable or not.