During the 1992 flashback of Jack visiting Nicky, Nicky offers Jack Nesquik, but the Nestlee company did not change Quik to Nesquik until 1999 (seven years later). When Nicky is stirring the drink, you can see a container of Quik, with 1992 or similar design.
The postage stamp on the Niagara Falls postcard to Jack is the 29¢ first-class mail Traditional Christmas Stamp, Madonna and Child (Bellini), 1992. This amount was greater than what postcards required at the time (February 1991 through December 2024), which was only 19¢.