Depends on where you are Pascal.
Off hand, the only state I know for sure titles outboards is Ohio, so it'd have to be separate BoS. Here in WV they ask for a model and serial# of the motor when they title a boat, but you can opt not to list it. If you did, it could be considered part of the boat, as it's listed on the boat title. So I choose not to list the motor. Again, it'd be 2 BoS.
So, where are you? NewYorkCity?