That is the product id of this leaked beta version, it is a trial beta and not activated.
No key code introduced by me after installation as I have none
I am not sure but probably you cannot activate beta versions?
Edit: yes beta versions can be activated. Found this information, if you activate you can use the beta version for more time.
Only difference between activated and non-activated windows 7 is that Non- Activated Windows 7 beta will work for only 30 days and geniunly activated Windows 7 will expiry on 1 August, 2009
When microsoft released to the general public the build 7000 it came with several Activation keys, and they ar eeasy to find. Note that the activation key is different of the Product Id.