Is it easy to retrofit the necessary rails to install headrests in a 1966 250se coupe? From either a w111 or w108.

When you installed the w108 seats, how did you get them to tilt forward to allow access to the rear seat? Is that mechanism separate? I just want headrest without having to find an entire post-1969 w111 coupe seat. Is that possible? Thanks!
Narayan