Hello All; On my desk landed a 1975 Omega Speedmaster professional Mark II. It was in a sorry state and water ingress was suspected. The last services were quite a few years ago, mid '80's towards the '90's. Those services were performed by a watchmaker working for a local highly reputable jeweler with a glossy facade. Instead of using the proper tools (a guide-ring) to replace the glass, for ease or necessity the official seal-ring was taken out and the glass was placed using a black seali