Surely he had to sign after reading the paper? The signature means that the paper has been accepted as it was. No he changes his mind... It is a little bit odd.People who did not believed him and insulted him before are so sure that he means what he says today. So the truth might be somwhere between?
Dozens protest in Shfaram against budget cuts targeting Christian schools (Haaretz)
from the article: NY Times: We turned down a different version of Goldstone retraction