Hum. I looked back at the archives here on the Allis board, and found where I once quoted out of the I&T book that the ensign model was kgn1 or kg1. If you have a copy, you can look to see what they say the kgn1 and kg1 look like (I think one may be LPG only) but I don't have access to one presently.
BUT I was able to get the AC parts book to open, and you will see that there it lacks the spacer I mentioned. See link.
So at this point I'd best bow back and let someone more knowledgeable help you, as I just don't know.
I will go on to add though that I just pulled up the Nb test and it states that the carb size was 1", but I don't see where it says the ensign model.