Anthony is wearing Adidas Popper Pants in the film, including the flashback scenes. If the flashback scenes were from eight years years ago, it would have been 1996. Adidas Popper Pants weren't released until 1997.
When Sonny, Soz and Herbie set off up the stairs with weapons to check for Richard's presence, they get to the top of the stairs in a different order than they started.