That is how I'm leaning. I think this entire season has been the Doctor rewriting things. The kicker for me was when he saw Amy and Rory at the mall. She is a big model for a perfume that has "for the girl who is tired of waiting" as a slogan. It leads me to think that it wasn't the same Amy and Rory who met him at Lake Silencio in the Impossible Astronaut but was the Amy are Rory that made no mention of her modelling career when Petrichor was mentioned as a TARDIS password in the Doctor's Wife. Further, though I'm not sure it matters, the front door to their house at the beginning of The Impossible Astronaut is wooden with glass in it while the one at the end of The God Complex is solid blue. So, to me, either there are two sets of Amy and Rorys out there or he has been actively changing their past leading up to the day of his death. Or, simply put, by sending out the envelopes he has altered everything leading up to Lake Silencio but not the event itself which is at a "fixed point." So, when he sends out the envelopes he got from Craig, he is sending them out to an Amy and Rory that are familiar with the situation.

Amazingly, I'm not stoned and this still probably makes little sense. Long and short of it, this season was never meant to be because The Silence and co. have altered the time stream since the recreation of the Big Bang at the end of last season. He is still going to die in this timeline. However, I think his death is going to set up to bring this wrong timeline to a close. Silence is going to fall on everything as it were.