However this watch has 15 jewels.
From close inspection, it appears that jewel bearings have been added. It doesn't look like factory work, but it is very good.
Elgin is known to have altered stock, changed some ranges of movements, before shipping them out. A few examples of errors made at the factory are also known.
But here on the top we see that some of the bezel screws are placed too far from the jewel bezels to function. The screws are supposed to hold the bezels in place. So it is good work, and these look like Elgin parts, but it's something some watchmaker did on their own.
Is this an exercise? Student work perhaps? Could it be from the Elgin watch college? There no way to know... I have seen a good deal of odd hacks in watches, but this is well done.
The watch functions quite well.