Alex talks about the Dow Jones Industrial Average moving to an astonishing base of 1000. By the end of February 1983 (the month this episode aired), the Dow had passed 1000 and hasn't fallen below that mark since.
Alex observes Mr. Matthews being harsh with an elderly lady. She turns out to be his mother. The same joke is used in the season 7 episode "The Job Not Taken". The Golden Girls used the same joke in an episode called "The Auction".
Alex's father says that the only stock they have is 50 shares of ATT. When this episode was made, in 1983, the price of ATT was about $60-$65 per share, so their entire stock holdings would only be about $3,000. Yet when they have a $2,700 margin call, the dad hurries to cover it to prevent the original stock being sold, despite the fact that the call Is virtually the entire value of their stock holdings and covering it would only save them a few hundred dollars.