What documentation are you looking at? I looked in the 75 MPC and all I found was how to install, an actual breakdown is what I was looking for. I got part number, C5ZF-7650615 from the body manual, D1AZ-76533A00-A from the MPC with a reference to a service kit, C3SZ-76533A00-A. The 66 Service manual has a breakdown but no "O" rings.
Besides, it's Florida. Leave the top down.
Jim