At first I thought the tail of the click was broken. That would be a strange thing to break, but you see strange things sometimes. On closer examination, someone actually filed to end off. I can not imagine why that would be done. I'm replacing the part with the intact one shown here.
This click's shape, on that end, isn't critical at all to the movement's functioning. But without that little tail there's nothing to push on to let down the mainspring from the outside, for maintenance. The plate has a little hole in that spot so the ratchet can be released.
Elgin number 4592421 is a grade 118, 6 size, 11 jewel, made about 1892.
