Been clearing up a lot of RPMs and other minor whatnots the last couple days. I set this one aside to look at later, which is now.
Pretty hard RPM to place, but I am semi-confident that it is 1MM-028. Didn't do one of those fancy pants line drawings but to me that's what it looks like.
So here is what I was looking at, note the split serifs visible top right and bottom left.
Then, trying to get a better angle I actually lost the split serifs but noticed something on the top left.
Seemed reasonable to just spin it upside down and the lighting shows, what certainly looks like, a third S to the northeast.
So just musing here that there might be another fairly wide S in there although possibly only visible on an early die state coin. Comments welcome.
Oh yeah, and here is the coin and the couple light die markers I could find, note the inside of the R in LIBERTY.