you didn't think that through very well did you....it's a birth certificate...same for a DD 214...kept much longer than that!
But spycatcher in post 3517 may have provided a clue:
The first tell are the folds of this document. In having examined documents of this period and more recent documents, they in group are all folded into these little office yello sized envelopes, usually with a window inside to reveal contents. For this to be a forgery, the forger would have to know exactly this process in which birth certificates are in copy handed out to the public. It might sound like a simple thing, but those folds are the one thing which someone would overlook.