I do… Depending on the vintage of the watch, I can replace crystals, seals on both the case-back, winding stem tube, and pusher tubes. However, I cannot provide testing or certification. Furthermore, I do not provide any guarantee of water resistance for vintage watches. If you have a vintage dive watch that you would like to use in water or diving I recommend that it be serviced by the manufacturer.
My main objective for vintage dive watches is returning them to working condition with reasonable water resistance. Use them for daily wear and enjoy them…..but don’t dive with them :).