How could it be a typo?

in the new nazi zombies map der riese on cod 5 on the official weapons list there are the weapons names and what their names are when you upgrade them. the type 99 and sawed off db are on that list. i know that there not in the game and the developer said it was a typo. but how could that be a typo. a typo is for example "watre" meaning to spell water. that is a typo. but how could you but the name of the gun and the upgraded name and its a typo. or did they mean to say it was going to be in the game but it was taken out. jut wondering. dont leave any smarta** answers either because im just curious