Old is relative and not a faithful reproduction. However, it is made "In the spirit" of the old possibles bag that the Mountain Man used. Buckskinning started quite a few years ago and along the way, many fine leather crafters have made some nice bags. There are a lot of cheap ones out there and I would say this is a nice one. Might have better luck identifying it on one of the Buckskinner sites. Have only seen one original possibles bag and it was in pretty bad shape. Doubt if many have survived. Powder flasks and horns are a different story. Might also want to contact the NMLRA.
Be Safe
Put it up for sale if you wish !!! ???