Starting with OmniGraffle 6, our app uses a single download file that offers both Pro and Standard feature sets. Pro features are unlocked when the appropriate license is entered or registered to your Omni Account, but the application will still be named OmniGraffle in the Finder, Dock and Menu Bar. You should be able to confirm that you’re running Pro from the OmniGraffle menu. Click About OmniGraffle, and look for the green text box confirming that Pro has been purchased.
You can also confirm that Pro is activated by seeing if you can access any of OmniGraffle 7’s Pro-only features, such as Shared Layers, Presentation mode, or SVG export.