That means, yes you'll have to install all those extras again. Whether or not that means they might not work as well, I can't see why if they're working currently. IMHO , "if it isn't broke, don't fix it" , with this quote I'll twist a little to mean, that it is better to use the repository to update anything that you suspect needs updating. If things are working well for you with an RC2 base, then you won't really miss too much compared to the Final. The Final DOES have some advantage as bug fixes were introduced, and the like,, but I would think that much of those fixes might also be applied in via the /patch section of the repository.
I think a browse over the change logs between RC2 and Final, might have more helpful information to guide you into your decision to upgrade or stay. Hope I helped by some way.