Need Help Identifying Caplock Shotgun
 

I'm trying to identify a blackpowder double-barrel shotgun. The only markings I have found on it are the tiny initials "LT" stamped on the underside of each sideplate, and the serial number 1558 followed by a capital 'I' (the letter following H). The 'I' is at a slight spacing from the numbers. This number is stamped on the underside of each barrel and the underneath rib at the chamber end. I would guess the gauge at something like a 20-gauge. There are no gauge markings on the barrels. The stock is walnut and the barrels are not marked as to gauge. I know this isn't much to go on, but I would appreciate any information anyone would be able to provide. Thanks!

OK, here's some more information. After careful cleaning, I found the following on the top rib. "(illegible).....CO. WHITNEYVILLE, CONN. HOMOGENEOUS WROUGHT STEEL E.WHITNEY'S PATENT OCT. 22, 18??" It's hard to read, but if I had to guess, I'd guess the last two numbers of the year might be 66. At least now I have a little bit to go on.

A quick google search revealed that Eli Whitney, inventor of the cotton gin, also dabbled in firearms manufacturing in Whitneyville Conn. He had a government contract to produce muskets. Start there.

Thanks for the response, Wingbone. I went on to find that Eli Whitney, Jr. (Eli's son) founded the Whitney Arms Company, and went on to manufacture a number of longguns and pistols. I'm still trying to find out the identity of the lockmaker whose initials (LT) are on the inside of the locks. I'd also like to find out the connection to the serial number and letter suffix.