There was/is at least one Thompson salesman sample, and it’s a live gun; it is not and never was a dummy gun. Colt 9962 was the personal sales sample of EE Richardson. The gun is currently in Form 10 possession of the Virginia War Memorial Foundation. I’ve seen and held it several times, and our own founder, Frank, wrote a very nice article about the gun for SAR back in 2019.
Here’s a link to the online edition of the article:
https://smallarmsreview.com/e-e-richardson-the-best-thompson-smg-salesman-of-all-time/
Edit: what do the lists say about the history of Colt 8946?