Hey Dan , I found a coin just like that a little while ago ... it is a 50 Centavos (2000) Eloy Alfaro.. it is silver colored but contains no silver . Here is a link with some info on it
I've found more Balboas from Panama than any other foreign coin.....with the foreign coins, I check the date, if it's a relatively new issue, I don't even bother.....I don't think there's any country putting out Ag coins these days (for circulation)