When they rob the bank, Joe holds the bag in such a way that money falls out. In the overhead shot later, there is no sign of spilled cash.
After Joe and Al win over $60,000 at the craps table, the cashier cashes chips in for cash. In reality, a win of that magnitude would require that a more high-ranking casino employee step in and have them sign tax forms before payout was made.
In at least two scenes early in the movie, the microphone cables attached to the characters are visible. Both scenes show the three stars photographed from a distance as they walk toward the camera on a very crowded sidewalk. The wire attached to Al's lapel microphone in one scene is plainly visible beneath his lightweight shirt. In a later scene, Joe has a visible mic cable outline leading up to his lapel inside his jacket.
Joe and Al leave Kennedy Airport in full daylight - yet don't arrive in Las Vegas until well after dark, an impossibility for a direct flight heading five hours west during the summer months.