The goof about the white socks isn't entirely accurate. In the scene Cliff takes off his right sock and shoe to kick the board that Norm is holding. Cliff never puts the sock back on. Instead he puts it in his pocket. So when Diane is carrying him up the stairs it is his right foot that is closest to the camera so there should not be a sock on that foot. I didn't notice if there was a white sock on the left foot.
The "Cliff Clavin" dummy that Diane is carrying up the stairs is much smaller than John Ratzenberger and is missing the white socks that he (Cliff) was wearing in that scene.
The NFL game match ups discussed for the football pool did not occur in the 1983 season.