Hi, intimidator,
The barrel marking could be the original owner or the maker. If a barrel was bought, the actual barrel maker's name was usually stamped underneath. But here is some info that indicates L. Adams was the maker:
From Small Arms Makers, by Robert Gardner:
"Adams, Lyman - gunmaker, corner Main and Division Streets, Utica, NY, 1832 directory. See also Adams & McCoy."
"Adams & McCoy - 4 John Street, Utica, Oneida Co., NY., 1848-1851. Probably Lyman Adams. The census of 1850 indicates that they had $1000 invested in the business and employed two hands at a total of $80 per month. During the year ending June 1, 1850, they purchased 40 gun barrels at $100, locks and mountings at $100. During the same period, they made 40 rifles, valued at $800 [total], miscellaneous articles at $700, and repairs at $450."
There is no indication of the markings on the guns, but yours would indicate that "L. Adams", if he was the Adams of Adams & McCoy, used his own name instead of the name of the partnership/company, or that he made guns separate (before/after) from the company.
That barrels, locks and furniture were bought rather than made was, as I noted above, common in the late percussion era before the Civil War. The information also shows a bit about prices, with a completed rifle selling for $20, a considerable sum considering that a skilled shop hand was paid only $40 per month, though he might have gotten room and board. (For a general price conversion to 2003 dollars, multiply by at least 50 in that era, by 40 in the 1880-1914 era.)
HTH
Jim