I can tell you about my current experience. My ex and I went to mediation because he believed it would be cheaper - not really! Well after we did the agreement we still needed to see an attorney to draw up the documents (settlement agreement & divorce papers). Any way I mentioned to the attorney I wanted to have my name changed back to my maiden name and this is being addressed in the divorce document. I don't know if this helps. I am still in the process of it and have not signed any documents yet. I would definitely consult an attorney. You can even call the social security office and see if they might know the answer. Now that I read my response I don't believe I was much help - sorry!! Wish you all the best in finding out.
In my case it is written down on the mediation papers that if I want to change to my maiden I can. I was asked and the mediator just wrote it down just in case in the future if I wanted to change it, it would be ok.