When Max has his protest sign "in code" where " would you believe" has each word spelt backwards, the word "believe" is misspelt backwards.
Just before Max puts the contract in his jacket in the wider shot, he moves the pen from his left hand to his right hand. In the closer shot, Max is no longer holding a pen in his right hand.
Smart reveals that he knew that the KAOS agent's gun was empty, because he identifies it as a Luger, which he says only holds six rounds. The weapon he takes from the agent is actually a Walther P38. In either case, both weapons, like most semi-automatics, have eight-round magazines.