Edith says it's 1am and they should go to bed, then the porter knocks on the door. No hotel worker would knock on a door at 1 am unless it was for something they ordered or an emergency. Mike and Gloria sent them champagne but they would not have done this at 1 am, if anything it would have been waiting in the room when they arrived, as would the gift basket from the manager.
Upon arriving at their hotel room, Archie is looking in the TV Guide and mentions that they can just watch Johnny Carson. Since Edith mentioned earlier that their anniversary is a Sunday, Johnny Carson wouldn't have been on TV.
Supposedly, the Bunkers' scene at the hotel took place on a Sunday night and Edith announces the time as 1:00 am. Archie wants to watch Johnny Carson on TV; although reruns of the Tonight Show had aired late-night Saturday and Sunday nights until 1975, it would've been over by 1:00 am.