The obverse is a mirror image. Old Joe 1887. Maybe it was used as a stamp. And then the reverse is not a mirror image except the J is oriented incorrectly. Old Joe Born Anytime 1887. I like it. Very interesting. Someone with more expertise in this area may post. Be patient.
I think before they put glue on envelopes they would seal them with wax, and there were special rings with designs and insignias that would make an image in the wax seal when you pressed it into the warm wax. I haven't seen anything like this, but it could have been used for that. I don't think it's a token. Someone else will prob. know what it is and what it is used for. I'm just guessing.
That's a very intriguing piece. It certainly looks contemporary to the 1887 date, based on the style, but aside from mentioning that, I have little intelligence to offer. I like it.