I have just personally completed reupholstery of my interior in leather from GAHH. This was a replacement of original MB leathers. First of all, the original plastic oval gromments for the headrest posts are medium/dark gray (not black), and the original headrest did not have grommets on each side of them. Please keep in mind that my 1970 280SL is European specs.
Also, I seem the disagree with Frank, I had my headrest stripped of padding, before replacement of new leather, and there is no way to adjust the amount of effort it takes to adjust the tilt of the headrest. There is a flat steel spring that is putting pressure on the headrest posts. The posts are "U" shaped w/90 degree corners and are attached to the headrest frame by this flat spring and some weld points and can not be adjusted. I even put some oil/grease around the post at the spring with no luck to make the tilting easier. Springs are tight.
So the bottomline is that the round grommets must have been for venting air pressure not for adjustments. Could it be that leather did not need these vents, because leather can breathe and MB-Tex can not???
Bob
Robert Hyatt
Williamsburg, VA.
1970 280SL, Red on Silver,4-speed, Euro spec; 1999 C230 Kompresser Sport, Black on Black; 1990 Miata, Black on Red, 5 Speed