I have done this modification before, but I am not sure about the Peugeot scooter you have stated. In the picture it looks like a Speedfight motor.
Anyway, a Piaggio Cylinder kit will fit on to the motor of a Honda Scoopy SH 50 (old model). It has the same bolt pattern as the older Peugeot Speedake/Speedfight. You don't have to fit a spacer unless the motor is stroked or 80cc. I do not know about the new model Peugeot's. They are not popular here in Bermuda.
Note: After I come from the shop today I will be able to answer that question 100%, if you are trying to fit a Piaggio cylinder onto a Peugeot.
Added Speed