1878-S Morgan Dollar - Mint Mark Question

This looks like "S" mint mark on the reverse die that was used on 1878-S VAM-78, VAM-98, VAM-127, VAM-128, VAM-129, and VAM-130. I can only find whole-reverse photos for VAM-127 and VAM-128, and the "A" was intact on VAM-127, and slightly broken on VAM-128. It might be worth trying to find VAM-129 and VAM-130 reverse photos to see if they match the broken "A" in STATES.

That's the best I can offer here.

Very interesting.

Here is the mm guide. https://vamworld.com/wiki/NEW!_1878...ntMark_GUIDE

And the Money Shots Guide. https://vamworld.com/wiki/1878-S_Money_Shots_Guide

You have the coin in hand, so maybe these will help you narrow it down. You can of course eliminate the long nock VAMs.