...but those documents weren’t available until this a few months ago. so a modern forger, would only have seen the 1936 DOB, and put his age at 25.
Okay, I re-read what you wrote. You may be right about every record prior to 1962 has the 1934 birth date on it, and every record AFTER 1962 has the 1936. Perhaps he was lying about his age because he thought immigration officials would be more sympathetic to a younger student? Hmmm...
Anyway, I took his 1936 date of birth on Barry's birth certificate as proof that Barack Sr. wasn't around when she was having the baby. I assumed Stanley Ann (or Grandma)put all the information on the birth certificate, and got the date of birth wrong, or perhaps he told her wrongly. The fact that there is no actual father's address listed is also a clue that Barack Sr. wasn't there.
Do you really think Barack Sr. cared about the birth of a kid (they were going to give away) enough to show up for it?
1962 is a key year, and it would be helpful at least to curiosity if not forensics to get a time line of the documents, date signed, signature used, dependents claimed, and birthdates(s) claimed.