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.
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.
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.