That's the one I used to install my headrest. The earlier 140's used the same headrest.

It was pretty easy to do. I would suggest redoing the webbing when you have the seat apart (you won't believe the difference).

Here's what you need (the plastic pieces are still available):



Note: the crossmember isn't needed to the '65 and newer cars.

This is what it looks like inside (you can see the worn out webbing sagging):



Paul