Thanks LIz - my Dad's birth information is a mess.
I know what day he celebrates his birthday (Feb 10, 1922); I have his birth certificate from Arkansas, which had a form letter 191_ for the year - and the doctor filled in "2" : so it says 1912 as his birth year. Also, it has written in very poor doctor's headwriting what looks like a "9" instead of a "10" for the day of the month.
The State of Arkansaw didn't start filing birth certificates until after 1912..
His National Guard discharge says he was born: Feb 10, 1919 - as he joined when he was 15, and you had to pledge you were 18 to join the National Guard: but in his small town in Arkansas, it was a way for all the teenagers to have rifles to shoot: and he joined up.
His Army Discharge from WWII shows he was born Feb 10, 1922.
His Death Certificate says he was born Feb 10, 1922.
He could have easily filed for Social Security earlier based on his birth certificate or his National Guard discharge, but didn't.