Concerning prove of address, I don't think there is any of such, atleast, FreeBitco have never announced any of such to the public.
And concerning addresses we know to belong to FreeBitco, I in particular have no idea of such, but I guess it won't be too hard to find if we should begin looking for that, and besides, I believe there are some of us here who must already have such address(es) handy, they can comment if they actually do have, but for me, I don't think I've ever withdrawn money from FreeBitco, so, I do not have any of their hot wallet addresses handy at the moment.

But by the way, I am curios to know why you are asking about this? For I am very sure that there is no casino that have a prove of addresses public, what exactly do you need this information for.