Looks like the lower serif is a RPM. But pretty minor on that area. I'd Keep it safe for now. (I always save all RPMs, even if they are not listed)
On the coppercoins website, they have spaces open. (1,2, 5-8) Those are reserved spaces for Mr Daughtrey's coins that are not listed yet. So one of those maybe like your RPM? Who knows for sure. Someday when you get a new major variety, you might include this coin to go along with the nicer new one you find to save postage.