No worries, not all is lost yet. Take the cover off the side opposite the primer and compare the diaphragm and needle. Place both carbs side side on a nice white towel or paper towel so you don't lose any of the little parts. You can then swap the new diaphragm and needle for the old ones on the OE carb.
Does the OE carb (Zama) pump fuel with the bulb? Just push down on the bulb gently and check for any tiny crack in