Arnold: from the beginning of the Smith hammerless in 1886, chambers were bored 2 3/4" unless otherwise indicated on the barrel flats.
1910 Norvell-Shapleigh, St. Louis catalog. $188 in 1910 is about $5000 today.
If you get the gun you might enjoy "The L.C. Smith Pigeon Gun" in
The Double Gun Journal, Volume 22, Issue 2, p. 110, 2011.
Some information here
https://docs.google.com/document/d/1rtqfXbMHv08c0iojRUFUV5kR7jIc-7jdinPZEmI9WSc/preview It is also possible that a Research Letter might document the original purchaser. If so, let us know and I'll see if I can find any information regarding the shooter.
https://lcsca.clubexpress.com/content.aspx?page_id=22&club_id=43784&module_id=245742 
