Yes, they are close, but the reason they aren't there yet is because there are still a few kinks. They're calling it RC0 right now, but I'm not sure what to think of that. The following definition is from Wikipedia:
"The term release candidate (RC) refers to a version with potential to be a final product, ready to release unless fatal bugs emerge. In this stage of product stabilization, all product features have been designed, coded and tested through one or more beta cycles with no known showstopper-class bug."
CM7 skipped right over Beta. It went straight from Alpha to RC0. Maybe the thinking is, with so many people flashing the nightly builds that suffices as Beta testing.
According to their post, it is still Alpha. Not Beta, Not RC. It is Alpha.
So, will RC1 == beta??? I don't know, but at this point, I would say technically yes because they are still putting in new features every few days. That, by defination, is alpha. Beta would be testing and fixing, testing and fixing. RC would be they think it is done, lets do one more full-on test. If a problem is found, fix and increment RC. If none found, release as final version.
Also, at this point, there is no bugtracker for CM7. That would indicate alpha, where bugs upcoming features are still internal to the devs. Usually, during beta, public bugtracking is provided to get everything working on a broad scale and to accept additional feature requests.