At the end of the first caper, Helmut is waiting for Hill in the apartment's underground garage and helps him into a Cadillac limousine. But the limousine in which they emerge onto the dark street in the next shot is a Lincoln Continental.
The helicopter that lands on and takes off from the heliport in New York is not the same helicopter that Jeff is shown boarding. There are different registration numbers near the doors of the two helicopters.
When Jeff and Helmut are talking at the heliport, the rear-screen projection behind them is done so poorly it becomes very obvious because of its shaking and graininess.
When Jeff turns on his penlight to illuminate the vault's dial, a studio light comes on a beat too late that throws more light on his face.