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?
Route 1 to Jerusalem reopened to traffic as fire outside of Jerusalem continues (Haaretz)
from the article: NY Times: We turned down a different version of Goldstone retraction