That looks like an old side-wind, hunter case, with a time-set pull stem visible, and it should just pop off/lift off the back-side cover, and some had a double back cover . looks at serial#'s and jewelers marking's from when cleaned serviced in the past . like anything else, the serial# will give a date of manufacture . then just start researching who the old manufacture Co. could be .
Case's most times has NO connection to the watch mechanical movement with serial #'s you see stamped , so get in to backside and look at the movement .
I only know of one local Smith in this area who is a real watch smith/jeweler . Most all the pre Korean war pockets were all mechanical, were pretty cool and all mechanical movement and parts back then were all hand fitted by a factory smiths, they were made in the 10's + of millions for volume worldwide . and even lot of the 15 - 21 jewel movements of Nicer movement Pocket watches are more of an appreciation of Mechanics that monetary worth .
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