So that means it must be a foreign country bond or a private bond issued by a bank or other entity within the US. Is there any more detail on who the issuer is?

If the issuer is still around, it probably is worth some money. Ideally it was issued by a foreign government, and like US savings bonds, it would still have the value, plus compounded interest. If it was issued by someone that no longer exists, then it has value as a collectible, and that value would depend on how rare it is and its condition