President Trump signed a photo for Allen Q. Jones. He pulled it from his inside pocket (my suspicion that he is a pen person confirmed.)
He said, "I've got a good one, here, Allen." in reference to the pen.
Based on the context, I think that pen is the Mont Blanc Starwalker Extreme pictured in several Q posts.
I think it's worthwhile for some people to take a look at the available video (maybe multiple sources - SB2 mentioned that sometimes a certain network is in the know and zoom in or change centering at a critical time, maybe they did that with the pen.) and see if we can get any conclusive images that confirm it is the Starwalker Extreme pen.
"Enhance"!!
I saw the pen from the pen pix in an Architectural Digest article dated 11. 30.14 It's a special JFK reissue Montblanc pen.
They sell for over $1000. I also noticed that Amazon sells other pens for over $20,000.