John: to date there has not been a documented factory “coach gun”, nor are there any period Hunter Arms’ or dealer advertisements showing a L.C. Smith “coach gun”.
Dr. Jim's Production Records lists a single 10g F grade hammer gun with a barrel of 27". There were 6 12g with 25" barrels. None shorter.
A single hammerless No. 0 12g had 24" barrels. There were no No. 00 12s or 10s with barrels shorter than 26".
The wide gap at the muzzle confirms the barrels have been cut.
We think, but can not verify, that the 'C' frequently found on turn-of-the-century Smith pattern welded and fluid steel barrels is for Crucible Steel, which may have imported the "rough forged tubes" from Belgium.