On my 87 560, the same colour is used in the trunk and in the bay for the soft top. It's a dark grey, but there's a greenish hue to my eye. On the trunk it does look like "primer"; however, elsewhere there are signs of (factory) touch ups, for example around the hinges, over joint caulking etc.

I would love to know what colour is used, as I have a little touch up to do. Anyone know?
Martin