AKM rifles are used by the Taliban operating in Afghanistan. Cuban soldiers in Michael Malone's (Kevin P. Farley) documentary "Die, You American Pigs" are also armed with AKM rifles.
AKMS
The AKMS,the folding stock variant of the AKM rifle, is also seen carried by Taliban members.
AIMS
A Romanian AIMS is seen in a pile of training materials captured in Afghanistan.
Single Action Army
General George S. Patton (Kelsey Grammer) carries a Single Action Army revolver (likely a Cimarron reproduction) throughout the film, at one point contemplating shooting Michael Malone with it.
Winchester Model 1912 Trench Gun
General Patton (Kelsey Grammer) and a group of World War II GIs fight off ACLU zombies with Winchester Model 1912 Trench guns.
Remington 870
When the ACLU zombies are attacking people in court, the judge (Dennis Hopper) uses a Remington 870 shotgun, handing one to Malone.
Colt M4 Carbine
When Michael and Patton travel to Afghanistan numerous American soldiers are seen armed with M4 Carbines.
Colt M16A1
During a country western music concert to benefit American troops, Michael Malone sees the ghosts of servicemen past watching over their modern counterparts. Only Malone can see the spirits of the soldiers and sailors from previous American conflicts, none of the other concert goers can see them. One of the first armed ghosts he sees is a Vietnam-era soldier, holding an M16A1.
M1 Carbine
During the same concert, Malone sees the ghosts of two Korean War veterans, holding post-WWII M1 Carbines.
M1 Garand
During the same concert, Malone sees a single ghost of of a World War II-era soldier, carrying an M1 Garand rifle.
M1903A3 Springfield
During the same concert, Malone sees the ghosts of two World War I-era troops, who hold M1903A3 Springfield rifles which are anachronistic for WWI.
Mauser Kar98k
Mauser Kar98k rifles were seen slung over the shoulders of German soldiers in 1938 when Michael Malone is thrown out of the window during the infamous 1938 Munich Agreement (where British Prime Minister Neville Chamberlain attempted to appease Adolf Hitler and Nazi Germany by having Czechoslovakia cede the borderlands region known as the Sudetenland to Nazi Germany) by General Patton. Two Kar98ks are also seen resting on a German tank during the 1938 Munich agreement scenes.
Enfield Pattern 1853
During the same concert, Malone sees the ghosts of two Union soldiers from the American Civil War, both carrying the Enfield Pattern 1853 (which was commonly used to supplement the .58 caliber Springfield musket that was the issued long gun of the "blue coats").
1728 First Model Brown Bess
Revolutionary War Continental Army soldiers are seen at the end armed with the 1728 British Land Pattern Musket, AKA the venerable "Brown Bess". These are the earliest models with the brass end cap and extended lock shape.
BGM 71 TOW
A BGM-71 TOW is seen in the American military camp in Kandahar.
Type 69 RPG
A Taliban members is briefly seen in the background carrying a Type 69 rocket launcher.
Trivia
Type 95 Light Tank "Ha-Go"
When General Patton walks Malone down the street after the signing of the infamous Munich Agreement of 1938, the pair walks past a series of armored vehicles and trucks being loaded by German troops. Incredibly, and rather anachronistically, there is an ultra rare Imperial Japanese Type 95 Light Tank (called the "Ha-Go"), that was mostly used in Manchuria. It sports a 37mm main gun and a 7.7mm machine gun. Why it is there in the background with an anachronistic German Iron Cross on the body is a good question.
Inaccuracies regarding WWII uniforms and conduct
Despite being a fantastical comedy/satire, the uniforms of the major dictators was unusual in that the color red was essentially 'de-saturated' from their clothing. Tojo's brown uniform was grey, and his red collar tabs were also grey. Hitler's mustard-brown coat also seems to be missing the red as well as the NSDAP arm band. Mussolini's arm patch would have had red stripes, but it has grey ones. This could have been an intentional choice to show that they are "ghosts" of the past, but it is worth mentioning. As for the guards or adjutants, German Heer and SS officers didn't hold a posture like U.S. Marines when at a meeting. When not "at arms" (i.e. not wearing their belts and pistols or other military weapons), they would have their hats off and arms to the side.