Sorting out a 280SL after restoration, and one task was to re-fasten the speaker grille. The problem was that the dash had been re-covered with a MB Tex-like product that was thicker than the original, so the original 19 mm screws were too short. Hmm. Not all that easy to find long-ish 2.9 mm chrome sheet metal screws. After some searching, I was able to find and order PN N007983-02218, 2.9x25 mm chrome screws. The only issue is that they are Philips head. Slotted head screws don't seem to be available in that size.
An alternative is #4 stainless steel SM screws in a 1" length, but they are hard to find as well.
Cheers,