The circlips DO NOT retain the RC Valve spindles in the barrels, but are there to help with their location.

I would say that it's not critical for them to be fitted, but advisable - else Honda would never have used them. You will most likely damage the seals if you remove them, but they are only approx £3 (US$5) each, so it's hardly going to break the bank! You do not need to use the Honda seals, any bearing/seal supplier will be able to match them.

Andy.
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