At the beginning of the movie in what turns out to be Willow's funeral, a shot of Wildman shows him in Dress Blues. At the end outside the chapel just before Willow's casket is moved to the burial site Wildman is seen in Class A (green) uniform.
When Sgt Goody Nelson reads the Army Digest, re Wildman's award of the Medal of Honor, and opens it for Hazard to read, the date of the citation is 1966, even though the film takes place in 1968 and 1969.
The flag on Willow's casket is improperly positioned while it sits at the altar in the cemetery chapel. The blue field should be at the back left corner of the casket (the blue field is always over the deceased's head, and the deceased's head is always to the left)
Much of the conversation in the film centers around how busy the Old Guard is because of the casualties from the Vietnam War. In truth, there are comparatively few Vietnam era graves at Arlington. Most soldiers were buried in their home towns. More Vietnam veterans were buried at Arlington after they died later in life than actual combat deaths.
SFC Hazard wears the 2nd award of the CIB, yet he states that 2LT Willow had always wanted to receive the "Combat Infantryman's Badge". He would know that the award is called the Combat Infantryman Badge - without the 's at the end.
In the beginning funeral scene, when the soldiers are folding Willow's flag, you see they are folding the blue field first, going to the red and white stripes. In the next scene, a pull-back, they are folding the flag stripes first. When a flag is folded, the blue field is always last so the triangle shows stars in a 1-3-5 configuration.
The actor playing Wildman is too short to have been a member of the Honor Guard. The requirement back in the 60s was to be at least six feet tall. Wildman is no where close to that height in the movie. Later the regulations may have been amended when women were allowed to serve in the Guard.
During the parade field ceremony sequence, the Old Guard is commanded to fix bayonets to the traditional beat of the drum. During this section, the salute gun battery is firing for each of the positions of the "fix bayonets" drill. This is incorrect. The salute gun battery does not fire at this time - they fire as part of honors for the dignitary on the reviewing stand, but not as part of "Fix Bayonets."
After the Old Guard Fife and Drum Corps performs the "Troop Step" in the parade field ceremony scene, there are four bass drum beats before the Fife and Drum Corps steps off to "Yankee Doodle." In actuality there are only 2 bass drum beats before the Fife and Drum Corps Steps off from the Troop Step into "Yankee Doodle."
During the funeral for SGT Willow, SFC Clell Hazard removes his CIB (Combat Infantry Badge) and places it on the coffin. Later, it is back on his uniform. Military badges are available for purchase at the post Clothing Sales Store and easily replaceable; Hazard would have done so immediately after placing his original on Willow's casket to be in proper uniform for the burial.
Willow is congratulated on becoming an officer. He is presented a paper saying he is now a 2nd Lt., and he is given a bar for each shoulder to signify his rank. A 2nd Lt does not simply wear "a shoulder strap without bars" since the US entry into World War I in 1917. A 1st Lt's rank is signified with a single SILVER bar on each shoulder strap; a 2nd Lt's rank is signified with a single GOLD bar on each shoulder strap.