Accord to Farsca & Hill, The .45-70 Springfield, they’re no definitive answer as to the star in the serial number. The authors guess that it could be an arm that was sent back for cleaned and repair. 1881-1882 stock dates.
The same machine that was used for the serial numbers, I guess was applied. There’s no way it was a hand stamp, from the orientation of the star and the depth.
A good arm.
Uriah