HI Brent
If you have any of experience letter from closed organization even without any job/ duties mentioned, then it can be used but dont forget it mentioned in your covering letter to CHC.
I had 3 years of experience from a organization and the same was closed a long ago due to some dispute. I mentioned it in my covering letter and send a copy (not original) of old experience letter without any job/ duties mentioned.
Thanks
Rajeev