Updating for the benefit of the next guy . . .
NOS front spring length (part #51457-259-010) for the CA77 is around 260mm. My originals were much closer to the NOS length than they were to the size stated in the manual.
Side note: I also ordered the metal cushion (part # 51420-259-010) thinking it would be the damper assembly shown on the CMS site. What I received (not from CMS, I should add) was the outer tube; it didn't have any of the internals. Maybe I just got unlucky, but if you're thinking of going the rebuild route, do yourself a favour and ask the seller what you're getting before you commit to buy.