Nicole...I don't know what state you're in but I am in TX and on my non-ID info that my reunited daughter recieved my correct and actual SS# is there. IMO what would be the point of adding anything if it was only going to be a ficticious number anyway? A reasonable person would simply leave the space blank or at best eliminate the space altogether. The difference might be that there was an agency involved and not an attorney. Not only did the documents list my SS# but maybe since I was a minor my mom's is also listed.
On the other hand there were so many secrets kept back in the day that nothing should surprise me anymore! Its a wonder they didn't assign us all one name like "Birthmother Brown" or "Placing Patty".
Good Luck in your search....MissyM