I don't think I phrased my question properly. Here is an outline of what happened.
My configuration prior to installation of Windows 7 Upgrade: System Disk = Windows 7 RC
1. Backed up all desired data to non-system internal HD.
2. Booted from Windows 7 Professional 64x upgrade DVD.
3. Formatted system disk containing Win7 RC
4. Installed without supplying CD-key.
5. Booted Windows 7 Pro 64 from HD after successful installation.
6. Activated OS with CD-key that came in Win7 box.
I bought the upgrade assuming I would 'convert' my XP license to a Win7 license by supplying my WinXP CD-key. But, I never had to prove that I previously owned any Windows operating system when I was installing Windows 7. Is this a flaw in MS's upgrading option and do I now have usable keys for both WinXP and Win7?