The twin plate clutch in the 2V bikes is usually fairly quiet when disengaged, (Lever out) and the flywheel and intermediate plate *Ring* when it's engaged, (Lever in.). The 8V clutches are the opposite.
The squeaking is almost certainly simply the intermediate plate moving slightly in the splines of the flywheel when it unloads. Probably assisted by a build up of dust in the splines. While the twin plate friction plates can fail, either by de-riveting the friction material or ripping the splined centres of the plates out by cracking the webs of the plate, this is rare at the best of times and tended to occur in certain years which I tend to think corresponded with the factory teetering on the edge of bankruptcy and getting cut off by their usual suppliers. That meant cheap, inferior plates and more problems. While I'm not saying there couldn't be an issue I honestly think it's unlikely, certainly the CARC bikes aren notorious for problems with the twin plate clutches.
Unless it's misbehaving in other ways, (Juddering or getting snatchy or the engagement point is changing.) I'd say put it back together and ride it. The only way to know if there is a further problem is drop the gearbox off and dismantle the clutch which is a bit of a chore.