When a child is adopted, the original is sealed. It cannot be released without a court order. Neither the State nor the Federal government wants individuals to possess two different birth certificates which can be used for identification purposes.
Obama's legal team may have requested the production of a new birth certificate rather than an unsealing of the original. I think the only person that could answer this question authoritatively is a lawyer or judge who has been involved in a similar process.
Of course, the question is, would it be obvious that Zero's BC is an amended BC?
Here's a case where it was obvious even to a creature as fascistically stupid as a Floriduh civil servant:
http://73adoptee.blogspot.com/2008/10/adoptee-denied-drivers-license-in.html
I’m somewhat confused. If what you say is true, then why would the Obama team release an adopted birth certificate, since the only way to prove NBC status would be with an original? Did they think it would deflect just enough attention, or that it would distract truth-seekers for another year?