My EPC for the w124 comes up with this number:
Group 74 - rear panel door :
"Loop on rear panel door interior part - code 844"
Partnumber 123 740 00 86
and as usual for an interior part, there is a footnote - No 904 -
giving the color in function of the interior number.
For a gray one it's No 7095 going together with interiors with color code 068 / 178 / 268 / 278 / 378 / 968.
Check out your code : Mb color codes and MY eyes don't allways
Hope this will help you out?