I have for sale rear headrest brackets and two good shape cardinal red headrests. 4x 10mm bolts and 4x black hole surrounds are included but not pictured. Headrests have no cuts or wavy piping.
$65 + shipping.

I can also leatherique redye them black for $15 more, but they will probably look so much better than your black seats thats not a good idea. Here's a seat I just redyed.

I also have one oddball headrest in good shape but it's darker than the pair above, more of a brown color. Not sure what the color is called or if its just cardinal that aged differently . It came out of an 86 325e.
$10 + shipping.
$20 + shipping dyed black.
tried to get a pic showing color differences, not easy though.
$65 + shipping.

I can also leatherique redye them black for $15 more, but they will probably look so much better than your black seats thats not a good idea. Here's a seat I just redyed.

I also have one oddball headrest in good shape but it's darker than the pair above, more of a brown color. Not sure what the color is called or if its just cardinal that aged differently . It came out of an 86 325e.
$10 + shipping.
$20 + shipping dyed black.
tried to get a pic showing color differences, not easy though.
