Upgrading from the RC? is it possible?

If a user has installed the RC in an all out attempt to be rid of Vista once and for all
will this work for the upgrade version being sold at present?
I am familiar with the upgrade process and one of the key elements to an upgrade is to have an O.S. install with a valid product key on the machine to be upgraded.
Is there a possibility that the Windows 7 team has created a way to just enter your previous product key of Vista or XP without having to resort to using it in the meantime? Yes they are both that bad.
Am i giving them too much credit? did I make a mistake by supporting the RC testing?
Common sense tells me I did both and yet again Microsoft is about to single handedly piss off a massive amount of loyal, warm and friendly people who supported their RC in the testing stages with thousands of error reports.

Microsoft posted an unrecommended workaround for in-place upgrades from RC to final.

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