I let my Mac developer account lapse a few months ago, but at least here's how it worked with Lion:
If you went into the developer portal and claimed the App Store redemption code for the beta, then you were automatically licensed in the store for the release version as though you had paid for it.
If you didn't claim it for the beta, then you could still claim it after the fact and get a license to the release version.
Yes, the codes for the GM should automatically be translated into codes for the release version. If you have the GM build installed then you should get the first update to 10.8.1 the same way that the rest of us do.
