Adoptee born June 30, 1928...Searching for info

Hello all, My name is Stephanie and I'm doing research for a family tree for my daughter. My husband's grandfather, Johnny S Goeders, was adopted by Frank F Goeders and Nora C Ferrell. I'm not sure when though. He was born June 30, 1928 in Oklahoma. It's suggest his mother was full blood Native American (tribe unknown) and got pregnant by a white man and had to give Johnny up. I'm thinking maybe he was given his name by Frank and Nora Goeders. I'd like help with this, any help will be very much appreciated.