How can I tell if I have TCF enabled?

There are subtle differences between a standard banner with- and without TCF enabled. The most noticeable would be that banner that does not have TCF enabled has three tabs: "Consent", "Details", and "About". When TCF is enabled, an additional "Ad Settings" tab will be available.
This tab will be populated with "Purposes", "Features", and "partners". This both provides information and allows a user to enable and disable each separately, or enable or disable all of these purposes, features, and partners.

Furthermore, you can tell if TCF is enabled by checking if the __tcfapi stub is available by issuing this command in the developer console in your browser: "__tcfapi" in window

This will return "true" if TCF is enabled. Conversely this will return "false" if TCF is not enabled.