Elgin Grade 350

There's an interesting prefix on the secondary serial number stamps on this movement. It's a stand in for "127".

More about Elgin serial numbers here.

This movement is a fine example of Elgin's railroad grade 350, 16 size, 23 jewels, made about 1907. 

This is a detail of the movement's motor barrel. See more examples here.

This is the top of the motor barrel, showing the mainspring arbor which is jeweled on this watch.

It's always a pleasure to see one of these fine timepieces.