They didn’t change the Coke cooler until the 40th Anniversary release. My guess consistency as well although if it was left untouched for the last 40 years what’s the point??

And yes my guess is the added Pepsi poster wasn’t done from scratch. You can clearly still see some matting effects so my guess is the Pepsi poster was placed over the optical as opposed to the unaltered poster.

Also looks like I was right about the mic shadow on the jukebox being added to the Rockin’ Rydell edition. The grabs I used above for the ‘original’ are from the 2002 DVD yet here’s a video that still shows the blurred logo on the menu yet the mic shadow is gone.