Mark Steyn notes that the recently deceased actor Peter O Toole had two birth certificates. One in July of 1932 from Connemara Ireland, the other in August of 1932 in England.
It really isn’t that hard to get false documents from civil authorities.
It was especially easy in the pre-Patriot Act, pre-identity theft scare days. There were books hocked in the back of magazines that would tell you how to create a new identity, with real legal documents that you could get from a few trips to the library, and maybe mailing a few requests out to other institutions for records. Also, in those days, it was all completely legal to setup such a false identity, as long as you didn’t use it to commit fraud or receive government benefits falsely.
Back in the 1930's in Europe there was a legitimate reason for some people to have two BCs. The birth month needed to be changed. August seemed to be the crucial month. A distant relative of mine was born in January but his BC says August. His parents and a priest did it when he was just a toddler. I found it strange that Peter O'Toole's 2 BC were one month apart. Something curious about August.