Swan is sitting watching his tape, after the car blows up on stage and sees the Phantom for the first time, in a black suit with a red shirt. When he comes out of the room and sees Winslow, he is wearing a tan suit with a white shirt.
Other places where the Swan Song logo is seen: A sign featuring the original unedited Swan Song logo can be seen in several scenes from within the Paradise, a towel Beef is wearing when he is getting into the shower on opening night and the tape player Winslow/The Phantom uses to discover Swan's secret deal on the night of Swan's wedding to Phoenix.
There are only two scenes in the film where you can actually see Winslow's scars under the mask, specifically on his chin. One is when he first attacks Swan in the hallway. The other is with Phoenix on the roof. At all other times in the film, there is no scarring visible anywhere on his face.
When Winslow is visiting the Death Records building for the first time, Swan Song Enterprises is visible above the doors. Swan Song was apparently changed to Death Records by the producers to avoid legal hassles with Led Zeppelin's Swan Song label.
When Swan is talking to the devil in the mirror, Swan takes the contract from him. However, when the devil says the words "in blood", he is still holding the contract.
The neon sign was and 'needs' to be on a wire. It can't function without electricity. Ergo, the wire was electrified and pointed toward center stage, just where it needed to be, and then held enough current to arc to the 'performer'.
Videotape was still only in the experimental development phase in 1953, when Swan records his suicide note/contract, and at that it was only capable of black & white images. Color, broadcast quality videotape of the kind depicted here was not available until the late 1950s.
As Phoenix is about to begin singing at her audition for Swan, the drummer does an 8-count intro with his drumsticks. However, you can see he doesn't begin to actually click his drumsticks until the third count/click.
When Beef comes alive, his song and voice and lips don't always "come together." Also, his voice is heard, mainly in guttural terms, but he is not singing. To expect that he had a prerecording for this performance, and that he was doing a back-up to his own vocals is not 'realistic", within this photoplay.
Brian De Palma can be seen at around 1:02:58. He's right there plain as night, in the darkness just over Phoenix's left shoulder, sitting in a director's chair with his right arm raised, along with another crew member over Phoenix's right shoulder, then he vanishes when the spot picks her up.
There's a shadow of the camera and the cameraman visible on the blue car at the end of the "bomb in the trunk" sequence.
Around 31:50, the cameraman's foot can be seen moving on the mirror behind Swan, as Winslow leaves the hallway.
In the film within the film of Swan's "suicide", the devil tells Swan that the image of him on the tape will age instead of him. Yet when the Phantom watches the tape, there is no difference in the appearance between the Swan on film or the Swan in "reality".
When Winslow/The Phantom stabs himself but doesn't die because Swan explains that because he's under contract he cannot die until Swan dies. Winslow then stabs at Swan to no avail as Swan explains "I'm under contract too!".
Yet when Winslow burns his taped contract with the devil and his face starts to melt and age his stab wound he got from Winslow doesn't open up and start bleeding like Winslow's does.
In the bathtub, Swan mentions that Saturday, November 19, 1953, was the day he wanted to commit suicide. November 19, 1953 was on a Thursday.