Non-Nikon (third party) silicone grease was commonly used without problems on black Nikonos o-rings by underwater photographers for several decades. Nikon replaced all these floods at first, but in the end, it clearly became not worth the trouble.
The use of third-party silicone grease on the black Nikonos o-rings was a common practice among underwater photographers for several decades.  Nikon's attempt to replace all of these seals proved to be costly and inefficient, leading them to abandon the effort.