The rifles being used by Kane and his men are M-1 Garands. This was the rifle carried by most U.S. combat troops during WWII, Korea and into Vietnam. The M-1 was a semi-automatic .30-06 cal. rifle that held an eight round clip. When the last round was fired, the metal clip would eject with a very distinctive metallic sound. The enemy would frequently use that sound to know that the soldier or marine was having to reload. Men would sometimes toss an empty clip to the ground while still having a round or two in his rifle. The enemy, on hearing the ping, would pop up only to have the U.S. soldier shoot first.
The house used as the Kane home, Foxglove Farm located at 6471 224 Street in the township of Langley, British Columbia, was previously used as the house in East Germany in 1982 seen in Jack's memories in The Gamekeeper (1998) as well as the Kress house in The Outer Limits (1995) Sandkings (1995).
"Caledonia", the name used for the rival nation, was the Latin name used by the Roman Empire to refer to the part of Great Britain that lies north of the River Forth, which includes most of the land area of Scotland. Caledonia is also the name of a town in Ontario, Canada.
The chevron badge worn by the tour guide at the beginning is the same symbol used on the mission patches on Stargate: Atlantis (2004).
In the final scene where Soren is in the bunker delivering a speech to his remaining troops, he holds up a handgun that very closely if not exactly resembles the handguns used by the Genai military, one of the first off-world civilizations the Atlantis expedition encounters in Stargate: Atlantis (2004).