After activation if you only look at the bottom of the screen there is option to activate the key, alongside upgrade to Pro.
However the top left of the screen shows after activation Blackbird Cleaner (Pro license with no free upgrades). So you do have the Pro version.
If you wish to upgrade the Giveaway Pro version in the future you would need to pay to do so, as there are no free upgrades for the Giveaway Pro version.
Best wishes – Howard:)