It's a Bartolini. Made by the Italian Bartolini Accordian Company. Hubert went to Europe with Howlin' Wolf in the mid-60s to play the American Folk Blues Festivals and likely picked it up there.
Pretty sharp looking machine. Check Google Images for pics.
Is the First Fuzz the 'Original' NKT275 or the 'Re-issue' NKT275version?
Does the FuzzFace have 'Original' 275's in it?
Excellent demo BTW.