Very interesting. This gun resembles guns made by Charles Slotterbeck in Lakeport, and San Francisco, Calif. he used this triggerguard (only often in iron), and the stock shape was very similar as well. Slotterbeck tapered his forestocks the same way, shaped his buttstocks the same way, and often included checkering at the wrist. A few Slotterbeck also featured back action locks. It would be interesting to know if they worked together at some time, or shared a mentor.
Hungry Horse