Even though Dean takes the Metallica tape from Sam, "Back in Black" by AC/DC starts playing.
In the original version of the pilot, the song they had there was "Enter Sandman" by Metallica. They couldn't get the rights to use it for the broadcast version.
Sam says "if it wasn't for pictures I wouldn't even know what [Mom] looked like," and has a photo of John and Mary prominently displayed in his and Jess' apartment. It's the same photo from Mary's nightstand in the beginning, but the frame is different, presumably because the frame had to be replaced after the fire. The photo isn't seen again, because surviving two house fires is a lot to ask of a photo.
