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.
For years, non-Nikon silicone grease worked well on the black Nikonos o-rings used by underwater photographers.  Initially, Nikon attempted to replace all of them, but they found it was not worth the effort in the long run.