Wayne, I'd go a few steps further because negative aren't stored in the light, so rather like cave paintings the risks of damage and deterioration caused by light are minimal. Then there's archives that are regulary worked with whose negatives would almost all have been made with Pyro based developers and we are talking about major collections here none of whom have reported issues of fading of Pyro stained negatives. In some cases the glass plate have been in use for making prints for well over 60-70 years.
Usually it's a case of finding (or proving) the cause of a known problem, however in this case it's speculation of a possible problems that's not been observed in practice in over 100 years.
There are other far less stable photographic processes like blue toning with Ferricyanide/Iron toners and kept in the dark they will last many years with no issues.