Whilst breaking into the house, the lock pick is upside down.
The photograph supposedly showing Colonel Stok boarding a flight to Amsterdam actually shows him climbing the steps onto a BAE Jetstream aircraft, a type which did not enter service until 2 decades AFTER the time period in which the programme is set.
GRU was actually formed by Stalin in February 1942.
The Soviet, Colonel Stok, is described as being a Colonel in the GRU, an organisation that didn't exist until 1992.
Modern heating or alarm control panel visible in the entrance hall as Harry enters the house where the scientist was held captive.
When the police break down the door of Dr. Radley's clinic they use a modern day battering ram which was not in use in the 1960s.
USAF Gen. Cathcart is shown wearing his rank on the shoulders of his shirt. In the 1960s U.S. Air Force personnel did not wear their rank on the shoulders of their shirts, but instead either on their collars (for officers) or the arms of their uniform coats.
When Harry follows Randall in the bus there is a conductor selling tickets, but both man pass him by without paying or the conductor even saying anything.