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Well, thanks everyone for the replies on Tuna in a Pouch!  
I received MANY notes, and here is the summary:

Starkist, packed in water, NOT VEGETABLE BROTH is GF
Bumblebee
Starkist Gourmet Choice Tuna Filet in a pouch,
and 
All chicken of the sea.

Only one person said that there was no tuna in a pouch that was GF. (I found that interesting, since everyone else said it was)

Many said to take little packages of mayo to add to it to make it better, but that the tuna in a pouch was better than in a can!

So, I think I'll try it!  
Thanks so much!
JAN

*Please provide references to back up claims of a product being GF or not GF*