Here is a price list that shows the differences --
Price List, July 1, 1882, pg 20.jpeg
The Laminated Steel barrel guns are Qualities I, K, L & M. The differences being gauge and grip style.
While these price list texts state "Fine English Twist" and "Twist" all I've ever seen on the guns is "Twist" & "Stub Twist" and of course Dean's examples of misspelling.