Yeah I always suggest putting the same into a machine...but with all the engine swaps these days you never know whats currently in there. That and the starters can be swapped.
Now, I have always told people to match them up b/c in my experence they can grind and disengage....but I just did one the other day that had a 9 tooth in it and I swapped to an 8 just b/c thats what I had, and it worked without issue.
Once of the biggest reasons to keep telling people to keep them the same are these cheap chinese starters. Thats where SBT made their blunder (they still wont admit it either) when they bind from the gears not meshing well it will snap the shaft right off. The chinese starters have super crappy steel being used for the shafts.
Those crap black starters...well I guess its the reason so many seadoos get sold to me cheap. I had one a few years ago that the engine was locked up. I pulled the pump and it was still locked, so once I bought it and got it home I pulled the brand new SBT starter (receipts showed it to be changed the summer before, charged $349 from a local clown) that was all it was. fired right up.
I just bought one in Chicago last week that his mechanic told him it has "no spark b/c of the starter" whatever that means. Nice mechanic; the customer was trying to find out what was wrong with it so he didnt have to sell it as a broken machine. I even suggested him doing it...b/c he was asking too much for broken machines.
This same mechanic charged them $500 for a starter swap last year. Yup...it was a $50 chinese one. Swapped it and it fired right up. Pretty decent XP for $250!