Renewing all the wear and potential wear components during a transmission overhaul will attain the best results.
Interfacing old, worn parts with new may lead to premature wear of the new parts and compromise long term durability, and ultimately reliability.
Other components you may wish to consider to aid you with a successful gearbox overhaul:
Add as many components as you wish to the same shopping cart, new nuts 920151963 washers 92022112922001065 & bearings 920461303 for example, and still only pay the same single fixed price shipping cost.
This component may have other applications within the Kawasaki model range, so check by part number rather than the description.
Pro-workshop gasket sealant 08C70K0234M easy to apply with pleasing results.