The station wagon Sickle uses changes from a Ford when the gold is being loaded, to a Mercury when its wrecked.
When Yo-Yo and the kids are chasing Dr. Gannon and Tony thru the streets, the weather goes from clear and sunny, to overcast looking like rain, and back to sunny again.
When the two children and Uncle Bene are walking away from the Rose Bowl, the camera pans back to reveal crosses marked on the ground for where the actors are supposed to stand and walk.