I can see no reason why the unopened one would not be good. Just open it and check, if it has gone bad it will show.
Same with the opened one, if it has gone bad it will show it. I could see the opened one being stale if it hasn't been kept closed up.
We have kept this stuff around for months and months, but always in an air tight container. I don't know what yours are stored in, but I was always told if it went bad you would easily be able to tell.