Elvis Presley is shown at Fort Hood, TX, wearing insignia of the 3rd Armored Division and 32nd Armored Regiment. He didn't wear that insignia until he arrived in Germany, where the units were stationed.
During Elvis Presley's first appearance on Toast of the Town (1948), the producers and director say a few times to shoot Elvis "above the waist". That actually happened the third time he was on the show.
Elvis Presley did not sing Little Richard's song "Rip It Up" as shown on his first Toast of the Town (1948) appearance.
Natalie Wood's wrists are bare in the late-night arcade scene. When Wood was 9, she injured her left wrist so badly that a bone protruded, leaving a scar. After that, she never appeared in public or on film without something covering her left wrist.
In the film, Elvis Presley is a teenager when he sings "Old Shep". In real life, he was ten years old, lived in in Tupelo Mississippi, and (according to one account) placed fifth.
When Elvis Presley and his band audition at the Grand Ole Opry, the electric guitar isn't plugged into an amplifier.
When Elvis Presley and his friends take over the arcade in the late 1950s, several racing games from the mid 1970s are visible.
In the movie Elvis Presley and Priscilla Presley are estranged, possibly separated, by the time he returns to live performances in July 1969. They actually separated in 1972. Several real-life photographs from 1969-1970 show Elvis and Priscilla together in Vegas.
The movie ends with a montage of Elvis Presley performing in 1970 over a slow motion of the actor's face. Elvis recorded the song used, "An American Trilogy", in 1972.