Looks like a Challenge Coin to me; I have just over 100 of these things I have gotten over the past years. In the Army higher ranks hand these out when we do a good job on something; in government service you can also get them for the same thing as well. I have gotten more since I have been out of the Army and working with Interpol because of all the agencies we work with, and or military units.
In regards to what it is worth. I always thought of mine as worthless and they get thrown in a drawer in my basement. I have seem people sell them but really who purchases someone else's award.
Maybe yours in the same sort of coin or maybe it is something else.
Appears to be no more than what is looks like: a token commemorating the centennial of Russellville, Ak. in 1970; a souvenir of the town.
You'd be buying the drinks if I put my Challenge Coin on the bar and you laid this commemorative next to it; but you may have fooled me for a moment. Interesting find, NWS.
Don..