Although the scene takes place 1992, while Rebecca and Kevin are at the card signing in the hobby store you can see the store promoting its Instagram and Snapchat accounts. This is apparent right after Kevin sits down, the logos are on the counter to the right of Rebecca.
The Sacramento Kings jersey hanging at the collectible store is number 5 Bobby Hurley who was still in college at the time, 1991. Hurley was drafted in 1993 in the first round 7 pick.
The episode takes place in 1992. The design of the Sacramento Kings jersey hanging in the sports store was not unveiled and worn until the 1994-1995 season.
When Rebecca walks into the sports memorabilia store, there is a Celtics jersey hanging in the window. The jersey is made by Adidas, which did not begin making NBA retail-sold basketball jerseys until 2006. Furthermore, the jersey is #5, which is Kevin Garnett's number. Garnett was not drafted in the NBA until 1995, which is three years after this scene takes place.
When Rebecca spots Kevin in the sports memorabilia store, a mom on the right side of the frame is wearing a Steelers wind-breaker. This jacket was released by Sports Illustrated as a promotional item for new subscribers in the late 1990s - well after this scene takes place.