Several comments. First, it is 1 of just 2 Crummey rifles I've seen that are worth owning, Al. A VERY nice piece. I certainly would have included this in a book had I had the opportunity to photo it.
2nd, the thumb: seems upside down. in southern end of Valley the thumbs seem to aim upward. In northern part thumb disappears.
In many older German cemeteries there is a hand with finger pointing upward, presumably suggesting the deceased was on his way to Glory. I'd guess that the pointing finger on rifles suggests true flight of the bullet. As to the position/ appearance of the thumb, I have no opinion.
I would wager my autographed photo of [censor here will delete name] that the lock is imported and only sold by Cofer. I owned a Cofer shotgun that was clearly a Belgian medium-low grade that he had over=stamped. Virtually none of Eastern Seaboard gunsmiths made shotguns; they sold imported ones [just like no one in USA seem to nake anything, it's red chinese].
In fact it appears to be an over=stamp. Still, period + most intriguing -- most b/c of working time! Cofer was not born until 1827 and last working date anyone has on Crummey is 1832! HMMMMMMMM
Now the only thought I have is that Cofer may have converted the lock and thus stamped it. It's possible but frankly I respect Cofer too much to really buy into that.
I doubt Wally or anyone else has published any of following on Cofer
Cofer, Thomas W. (1827-1885). gunsmith. 1850, Nansemond County, living in Richard Riddick Sr’s inn. 1861-62, Portsmouth. Thomas W. Cofer was born in 1827 in Isle of Wight County, Virginia.. He married Margaret A. Sanders in Gates County, North Carolina, on 13 May 1852. They later resided in Portsmouth, Virginia. Cofer died in Portsmouth on 23 July 1885. He invented a revolver that could fire fixed cartridges or could be used in a traditional way as a percussion arm, for which he received Confederate patent 9 of 12 August 1861. These very rare revolvers are considered secondary Confederate arms although there is no known C.S.A. order. A number of quality shotguns bearing his name have been located. 1872 Portsmouth Directory, Cofer T W., gunsmith, 15 Union, home, Clifford, corner of Court, Portsmouth. 1880, Portsmouth; wife Margaret [Census]. 1880, Cofer, gunsmith, 52; Margaret, wife, 51; Rich, 24, book-keeper; Wm, clerk, 21; Marg. L., 19; Walter Simcoe, son-in-law, clerk, 31; Annie, wife, 26; Lucile, 3; Estelle, 2 [Census].