Call it what you may but LAC guns & Ithaca built Lefever Nitro Specials share nothing in common, but the name Lefever, they are totally different guns, built in a different time frame.
The discussion concerning Foreign Proof Marks & SN sequence's was concerning LAC guns which was made plain at the beginning of the thread. Nitro specials were not even being built when this was taking place.
All LAC built guns do share several common features, though there are indeed design changes over the years.
Some of the barrel makers mark are GL, I believe this one is on Damascus barreled guns. I have SB&CO marked barrels of both Damascus & Smokeless & there is as I recall LLC marke smokeless barrels, I believe this one is more often found on Ithaca assembled guns, though not certain.
It could also be said that Purdey's & Crescent's share some common features, they are both SxS doubles, many have two triggers & both are sidelock's. "WHAT IS THE BIG DIFFERENCE" between them. If you understand that you should well understand the difference between an LAC gun & a Nitro Special. They are simply not in the same category of either design or workmanship.


Miller/TN
I Didn't Say Everything I Said, Yogi Berra