Thompson Center should be the company that you are looking for.
Not published in any reference.
They are called BT-99 shotguns
You will have to contact RTM to find out.
George Worthington was a hardware store in Cleveland, Ohio, from about 1890 to 1935. Single barrel shotguns were marked with his name by Crescent Arms Co and double barrel shotguns by J. Stevens Arms Co.
go to gunbroker.com and you'll see all you can handle.
100 to 150.00 dollars in good condition.
Numerous companies in many countries have made single shot 12 gauge shotguns.
on a single shot barrel you must remove the barrel and look at the flat side underneath the chamber to see the choke stamping.
See www.chuckhawks.com Fox shotguns
Revelation was a brand sold by Western Auto stores and made by various manufacturers.
Single shots, $50-$75. Double barrel, $150-$250.
Many early shotguns were single shot muzzleloaders. Some were double-barrel with barrels arranged side-by-side. This is also true of later breach-loading shotguns. The action style for these single and double-barrel breachloaders is 'break-open'.