Is oyster sauce gluten free

I have looked everywhere and there's only one brand that I've found that is gluten-free. Wok Mei which is sold by honestfoods.com and now on Amazon. They also have a gluten free hoisin sauce. Have not tried either yet but the reviews are good.

Just an fyi. I'm Celiac and was diagnosed 2 1/2 years ago. I have managed to eliminate the gluten from my diet. I cook authentic gluten-free Chinese food about 3 times a week. What I'm trying to say is you can trust my info.