I'm fairly certain it's inevitable that, eventually, they'll find out the truth about our gangster duo. I wonder if mr. Guiderone will use it as leverage later on, or if the FBI/CIA/MI5 whoever's chasing after us decides to try and openly bargain with Abi and Brooks, reducing prison times if they lure the others into a trap...who knows. It'll come to light eventually - just not in the near future.

EDIT: I should probably mention that Abigail's deceptive nature will probably be obvious VERY early on as I have no doubt we'll be needing her acting skills to get out of sticky situations. Hell, if she can get Eli to lower her gun, the world's her oyster...