(Freightliner 2013 isx15)starter 11 tooth or 12

Need some help here , I'm going to replace the starter on my cummins isx. I went to the dealer in the morning to buy the new starter, the guy at the counter brought me a delco remi 39 MT model with a yellow sticker stating that the unit was only for dd13/15/16, 2015 and older. I asked him about the sticker and he said it was fine. I paid for the unit and went home. Now looking in the delco remi website i found a pdf file with all the info on the differences models . 39 MT for the isx is a 6/8 pitch 11 tooth and the one i have is a mod 3 12 tooth. Does this make a difference? Should i get the starter with 11 tooth for my engine? Thanks in advance.

 

Yeah i would do that, thanks for the reply swaan.