You're missing something. It says "filed" because they all say "filed". The fact that the date is 4 days after birth rather than a year is not evidence of alteration; it is evidence that Ms. Ericson's claim that Obama's certificate was filed over a year late is just totally wrong.
Actually, no, they don’t all say “filed”:
http://farm4.static.flickr.com/3084/2601778875_496cabb303_o.jpg
says “accepted”...