The bites, from Curly, of the rivet change from a few to none when Moe notices it.
Larry breaks character when Curly shouts the line, "Don't mind me! Don't mind me!"
When Moe knocks Curly on the head while trying to get his sweater off, Moe falls off the truck, but Larry catches him, you can hear Moe, out of character, saying thanks to him.
When Moe, Larry and Curly climb on the steel girder to get taken to the 97th story, if you watch the shadow of the steel girder and cable that is lifting the boys up it only goes up about 8 feet and then stops.
The wire is visible pulling Curly back numerous times when he is slipping on the oil.
When the parachute covers the Stooges car and they drive away for a brief second you can see the shadow of the boom mic reflected on the upper left portion of the parachute.