Looks like a bog stock ETA 2393. Image courtesy Dr. Roland Ranfft's movement archive. Serviceable, but not exceptional. As to the regulator, the tail with the gate and curb pin are there, but the finger appears to be broken off. The watch could still be regulated. Note that the regulator on the Ranfft ETA 2393 never had the finger. Could be a donor part without the finger was added to your watch.
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