Thank you so much.

I could see no way of identifying it

Without personally knowing Jeffery and what brand accordion he plays, and without a close up video in the front of the accordion, there is no way to tell who the builder is. Most "handmade" Cajun accordions have the same characteristics from a distance. The only exception to that would be, Junior Martin has a patent on the "crawfish" bellow and Randy Falcon has done a few with an eagle ( close to a "falcon" ), so that could be used to identify the builder. I assume that JB knows Jeffery, or at least knows that he plays a Bon Tee, so that would be a good reliable answer to your question Doug.

Not acquainted with Jeffery yet, unfortunately, but he does have a great website. Man, does that Dude travel!
Looked for some good photos on the site that could be enlarged.
Found one on his Press kit page and one on the Photos page that showed the engraved brand on the keyboard side. Both instruments said Bon Cajun.
Compared the photo on the website with the YouTube photo. 99.9% sure it's the same box.
Looks like he also plays a Gab 3-row.
Went to Mr. Larry's site and pulled up his phone and address, etc.
Pretty simple.
Thanks, Jude.
JB

Ace detective work JB !

Does anyone have any idea who the maker of this accordion is?

That's a Gabbanelli King.