The five volume set "The New York State Firearms Trade" by H.J. Swinney and compiled by Tom Rowe lists only two Sweeney's as gun makers in New York. One is a Charles Sweeney in New York City in directories from 1833-1835 and 1840. In the 30's he was listed on Division Street and in 1840 he was at 390 Monroe. The other, John Sweeney was from upstate. His obituary, which appeared in a Battle Creek Michigan newspaper in 1886 says that he was "...born in the township of Severn, Ontario Couty, N.Y., June 19, 1804...He learned the gunsmit's trade in Geneva and afterwards ran a gun shop in Starkey, Bloomfield and Dundee. In Bloomfield, he was married to Mary Wheeler. In 1833 he removed to Ann Arbor (Michigan)..."
They further state that he might have been apprenticed to Castle Southerland who wound up in Ann Arbor. Perhaps that's how Sweeney arrived there.
While the firearms of many of the makers in these books are illustrated, there are none attributed or identified to either of these Sweeneys.