In order to legally be in possession of an NFA item that is owned by a trust, you just have to be a trustee. I make sure to have a copy of my tax stamp when I'm in possession of an NFA item, but how would anyone know if you were a trustee at the range or anywhere else you might be questioned? I've never thought to carry a copy of my 32-page trust with me that says I'm a trustee.
My guess is I'll never be asked and a copy of the stamp would be good enough. However, it seems to me in lieu of lugging around a copy of your trust there's no way to prove you're legally able to be in possession of an NFA item.
My guess is I'll never be asked and a copy of the stamp would be good enough. However, it seems to me in lieu of lugging around a copy of your trust there's no way to prove you're legally able to be in possession of an NFA item.