Jon,

I believe the headrests are held in place by a sort of a u-shaped clip. One
side of the "U" is straight while the other side is bowed to the shape of the
headrests posts. The straight side slips into small cuts on the headrests
posts and serves to retain them in those different positions. Same clip can
be found in other watercooled VW's.

BenT
San Francisco