The word "yuppie" first appeared in print in March 1983 and didn't become commonplace until after the publication of "The Yuppie Handbook" later that year. Two characters in 1981 describe the law student/bartender as a "yuppie".
The song playing during the opening credits, Bow Wow Wow's version of "I Want Candy", which was also the video playing on the TV behind Ben Affleck in the bar, wasn't released until the next year, 1982.
In the taxi cab when the taxi driver is talking to the two women looking for dates, the lights from the disco ball are rotating one way on the women and then in the next shot, it is seen rotating the other way on the taxi driver.
As Monica is putting the needle on an Elvis Costello record, there are two albums propped up against the wall behind the turntable: "My Aim is True" and "Armed Forces". In the next shot, they are gone.