Mikolas or Mikula

I am trying to find information about my great-grandfather (John Mikolas) who came to America Nov. 1880 aboard the Nurnberg and his family before they left the old country. He traveled with his Father (Johann) and his Mother (Rosine Cernoch) and his 2 sisters. I have found a possible link between a Johann Mikolas and a Joseph Mikula(s) – brothers maybe – however I cannot confirm that the Johann Mikolas is the same person as my great-great grandfather? I am hoping someone out there can help me confirm or refute this information. Thanks very much