Typical RV EPDM rubber roofs were installed with a white coating. Over years of use and storage, the EPDM will shed the white coating, leaving only the underlying black material.
There are a few after market coating products sold. Dicor is one trusted brand. In '96, typical sealants were butyl tape and maybe an OEM caulk. Previous owners may have been up there trying to seal the roof. If it was me (and it was, once), I'd remove any old sealants and replace with Eternabond tape. Look on the
Eternabond website and see how surface prep and installation is done. This tape is a lifetime sealant.
Also, you may have some frame and floor damage (likely) from water intrusion. It can be repaired.