I have located my grandfather's Michigan death certificate from 1939.
Following his father's name is the abbreviation "(O.K.)". What does that mean?
According to the information on the death certificate:-
your grandfather:- Irwin Blake his father :- Charles Johnson - Swedish his mother :- Augusta Svenson
I'm am wondering why his surname is Blake as it doesn't seem to have any correlation with either of his parents.
It's not Johnson,Charles or Charleson as you might expect. And similarly with his mother or something assigned on entry(as he's born in the U.S.A) - apologies to Bruce.
Looking at other questions and their answers. I found that the United States follows the common law, where it is okay to change your name as long as you aren't doing it for fraudulent intent -- all you have to do is begin using the new name. Perhaps that is the case in this instance.
this is found here:-
and has other information regarding name changes.