Striker plate gasket — a genuine BMW part, number 51 21 8 124 668. The number stamped on the part is 51218124668; BMW's catalog files it under the short number 8124668. You will find it on our Interior Body shelf, under Other Body equipment parts.
It fits every E36 body style (318i, 318ti, 320i, 323i and 325i, 1992–1999), with the M40, M42, M43, M44, M50 or M52 engines — and the European-market versions.
BMW draws it on 2 diagrams, among them Door lock front (41_0939) and Locking system, door, rear (41_0940). BMW's catalog calls for two of these at each place it is fitted. It weighs about 4 g (under 0.1 lb).
We have not had one on the shelf yet. Request it and we will tell you when one comes off a car.