In the opening sequence, Moe is paired with Stella, Larry with Mella and Curly with Bella. At the wedding, Moe and Curly have switched girlfriends... Curly marries Bella, and Moe marries Stella.
When Curly runs into the glass window while Moe and Larry are thinking you can see Curly's stunt double and his bald cap is noticeable.
When the Stooges first try to gain admittance to the party, a man tells them you have to have formal attire to get in.
However once they knock him out so Moe can get his tuxedo, there is really no need to have to wear formal attire anymore since there is no one else there to check what you are wearing.