We are now nine months into the "New 52" in the DC Universe. Many felt this was something that would be reverted right away. That doesn't seem to be the case as everything is moving forward.
As we're still seeing little changes and tweaks to the characters we were familiar with for years, the big question has been, did everything that happened before actually happen? Has all the previous events simply been erased as we get accustomed to this new comic universe? Many events have still happened in some fashion but others clearly cannot have happened.
With the appearance of Pandora, the mysterious glowing pink lady, we saw at the end of FLASHPOINT that it was her intention to combine three timelines to create a new one. It was also at the end of FLASHPOINT where Barry Allen, the Flash, received a letter from that world's Batman, Thomas Wayne, to deliver to the Batman we know, Bruce Wayne. Because of the letter, is it possible that Batman and Flash know Flashpoint happened and that there could have been a different world before that?== TEASER ==
It was Pandora's little speech to Barry that confirms the Pre-New 52 world did happen. She combined three timelines to create a new one because "the history of heroes was shattered into three long ago." Because the "New 52" stems from this moment in FLASHPOINT and this Barry Allen was from the pre-New 52 Universe, that Universe happened. So readers that are upset over certain stories being erased can hold onto the fact that they still did happen back then.
Once Barry returned to the newly created "New 52" universe, he found himself at work but made his way directly to the Batcave to deliver Thomas' letter. He informs Batman of everything that happened. That he tried to save his mother and ended up changing history. He mentioned his memories from his world started fading each moment he was in the alternate timeline just as he likely doesn't remember everything that happened during Flashpoint.
The memory of Flashpoint and the conversation they had about it can't fade from their minds. The letter that Flash delivered was from the Flashpoint universe's Thomas Wayne. Bruce still has the letter. We saw in JUSTICE LEAGUE #9 that he actually has it on display in the Batcave. Because of Bruce's nature, it would make sense that he would look into where the letter came from. He told Barry that he even thought about trying to save his parents if he could.
Knowing that Barry caused Flashpoint should arouse suspicion as to what else might have changed. Bruce even asked, "But now everything's back to 'normal'?" Are they simply assuming that the world Barry was in before Flashpoint was this same exact world? Would Batman be content with just accepting and living with that assumption? Why did he use quotes around 'normal'?
Batman is not one to sit back and accept things. This is what we saw in regards to the Court of Owls. Young Bruce was sure of the Court's existence and pursued every possible avenue to discover if they existed or not. He was wrong in his findings but he did do everything he could to find out. He would do the same thing with the letter and the world that came before Flashpoint. As a detective, it's just part of his nature.
Barry's memories about the Flashpoint world may have faded for the most part but does that mean they're completely gone or is it he just can't access them? With all the telepaths and magical allies they have, would they try to get someone to try to access Barry's memories to see what the Flashpoint world was like as well as the one before? There's just no way Batman would accept that this was the only existing world. Knowing that his father could have written him a letter in an alternate timeline, he would want to investigate the possibility that Barry's actions might have altered other things as well.
The idea of DC having a backdoor to return to the pre-New 52 world is a nice idea. It doesn't seem likely that they would actually use it based on how things are going. If that was the case, there's no reason for Batman or Flash to remember or know about what the DCU was like before. It seems suspicious that the letter was shown again in JUSTICE LEAGUE. It's just a matter of time until we see further investigation into this unless we're just to assume the possibility will never cross their minds.