Can you share a quote from the reference you found on this point?
the US Copyright Office has an
FAQ page. It says, "In the case of photographs, it is sometimes difficult to determine who owns the copyright and there may be little or no information about the owner on individual copies. Ownership of a “copy” of a photograph – the tangible embodiment of the “work” – is distinct from the “work” itself – the intangible intellectual property. The owner of the “work” is generally the photographer or, in certain situations, the employer of the photographer."
BUT there is also an abandonment clause that states I do have a right to them if I have tried to contact the photographer or family of. I would have also have to state that these are not mine if I publish them.
Before I decide to do anything I'm going to have a talk with my lawyer and see what if anything I can do.