I clicked on the Apple logo and selected About this Mac and browsed the information in the Overview tab. I expected to see the AMD graphics card info in the summary but I did not. Then I remember vaguely the articles weeks prior noting an issue with the 2016 MBP’s showing “incorrect” graphics card information. Like many others, my graphics card information implied the integrated Intel GPU was this only GPU. So I got the idea that maybe I can force the AMD card to be used and check About this Mac -> Overview again to see what it will say. I went into System Preferences -> Energy Saver and automatic graphics switching on and off, each time reopening About this Mac and looking at the graphics information in the Overview tab.

With the automatic graphics switching turned on:

 

Now turned off:

 

Now both the integrated and discrete GPUs are present in the graphics information in About this Mac -> Overview. I suspect this may have something to do with this, but more analysis is needed and I may not have this time.

Oh, and I found what may be a bug regarding QuickTime and the automatic graphics switching. Filed bug report 29451453 with Apple.

[Update 12/3/2016]
Apple said the “bug” was not really a bug.

[Update 12/18/2016]
macOS 10.12.2 fixed this.