Regarding his playing the piano, Jensen Ackles had this to say at the Asylum Europe Convention in Germany in 2010:
"That's what we call movie magic. I will say that I took two weeks of piano lessons for that scene. It wasn't me entirely, but when the camera was on my face and then it went down and you saw my hands, that was me. I learned about eight bars at the beginning of the song. I'd rehearse it and rehearse it and rehearse it and rehearse it and it wasn't perfect, but it was good enough to where it looked like I knew what I was doing, and then they would cut away to the hands and that was a professional piano player."
"That's what we call movie magic. I will say that I took two weeks of piano lessons for that scene. It wasn't me entirely, but when the camera was on my face and then it went down and you saw my hands, that was me. I learned about eight bars at the beginning of the song. I'd rehearse it and rehearse it and rehearse it and rehearse it and it wasn't perfect, but it was good enough to where it looked like I knew what I was doing, and then they would cut away to the hands and that was a professional piano player."
The date at the end of the episode, as seen on the tombstone, is Oct. 21, 2020.
Max's phone number, clearly heard near the beginning when dialed by Logan, is the first 9 notes of the theme song to "The Wheel of Fortune."