I would like to buy the rear seat headrests but I'm a little confused:
the rear seats on my 81 300TD wagon have 4 chrome fittings on top with what appears to be rubber-lined holes in them facing forward, not down into the seat???

Are these for some other function other than rear headrests?

I recall on my 85 those were there to position the seat back when it was folded down

Lift up the rear seat cushions and you will see the pins that those "chrome fittings" line up with. Rear seat headrests I think were an option that came with the rear third seat option. The rear headrests act as headrest for the third rear facing seat as well.

__________________
1999 MB SL500 (110,000 mi)
2004 Volvo V70 2.5T (220,000 mi)
2014 Tesla Model S 85 (136,000 mi)
MBCA member