Homesteader, I looked at the photo of your L.C. Smith, and am extremely skeptical that this is some original and rare grade or variant. More like 100% skeptical.
Take a good look at the picture. The lock is stamped L.C. Smith in the usual location. There is dark grime, dirt, or whatever down in those stamped letters. Then look at the crude "Mark's Special" engraving. It was obviously added after the gun was case hardened. We can see remnants of the original case hardening colors. Engraving is almost always done before case hardening, because it is much tougher to cleanly cut the case hardened surface. The engraving cuts are shiny and not filled with the same grime or dirt that is seen in the stamped L.C. Smith lettering.
There is nothing here that should compel anyone to go off on a wild internet search, looking for some old defunct Mark's Hardware Store or Emporium that might have commissioned Hunter Arms Co. to produce a shotgun with Mark's name on it. There is nothing here to remotely suggest this was built as a presentation gun for Mark Twain, or Mark Zuckerberg either.
I suggest you start a new thread, and let this one die... again.
It might be entertaining to start a new Thread, just to see who might be naive enough to think you have something almost as rare as the Czar's Parker. I'd suggest you simply accept the gun for what it appears to be... a well used 00 grade L.C. Smith that has been altered with crude added engraving, well after it was built. It is not some rare variation that would be the heart's desire of any intelligent L.C. Smith collector. If it is safe to shoot, then use it as a Rainy-Day-Loan-it-to-Your-Brother-in-Law gun. Don't waste good money on a Factory Letter as you were advised on the L.C. Smith forum. Keep the money to buy some appropriate low pressure shells instead.
