Board Thread:Theories and Speculation/@comment-38812954-20191014152438/@comment-32685487-20191015040036

No you have to have the dna of the two reincarnates, or if you are an rincarnate already you get the dna of the other incarnate like Madara and Sasuke did. Zetsu said something that hinted that an Asura reincarnate could awaken the Rinnegan too, so I guess if Hashirama was to take Madara or Sasuke's eyes he would awaken the Rinnegan and/or SPSM.