Does anyone know what this part is?

[Gericho]

I found this piece of rubber floating around under the tonneau cover (hood storage area) of a MK1 C70 convertible. It appears to have broken off something and its not plastic.

Also can anyone recommend a specialist who can fix or replace roofs on the MK1 C70 convertible?

[Super Sonic]

Looks like some sort of retaining plunger.

[E-bmw]

That looks like to top of an adjustable rubber bonnet stop.

The ones you come across at the corners that you can adjust up/down to get bonnet gaps even.

Could be that the same thing exists for setting where the roof sits.