Rebuilding the head-stock assembly is always going to be easier and more straightforward when new, correct specification parts are specified.
If the adjustment nuts, seals and bearings are all replaced at the same time the results will be as close to perfection as it is possible to achieve.
Renewing the ancillary items will add to the overall aesthetic of the triple-tree area of the machine.
Other headstock related parts you may wish to consider:
Achieve perfection by renewing as many of the wear prone parts in the head-stock assembly as possible.
Add as many components to the same shopping cart as you wish, new nuts 9017925004 and washers 902022614226H2341801 for example, and still only pay the same single fixed price shipping cost.
This part may have other applications in the Yamaha model lineup. So, please ensure the part-number/s you order are correct for your model.