Billy is shaving with shaving cream on his face while talking with Channe, but in the very next shot the shaving cream is gone.
The family is watching Thunderbolt and Lightfoot (1974) on TV, which was not even released to theatres until 1974, but we later see a date on a gravestone of 1973 (which means the TV scene was probably set in 1972, since there was an intervening New Year's Eve scene).