.
Is it? I had it on the authority of a good friend, an honest man (former contributor to a particular trad outlet, in fact) who had it from a family member it happened to.
Should I bother to ask what this person's name is? I can't exactly prove a negative, but I do know that Bp. Dolan gave people the sacraments who went to the
una cuм Mass, so for an even greater reason it would make even less sense to refuse the sacraments to someone who held a different brand of sedevacantism than he did.
The idea of a sedevacantist chapel refuses the sacraments to people for holding a different theory on sedevacantism than they do is something unheard-of in America* since Vatican II, and it is highly unlikely that a place such as SGG, which is definitely on the easy-going side of things in the trad world, would be the first place for such a thing to happen.
* I exclude the SSPV from this statement, though they are more or less sedevacantists, since those people are crazy enough to do almost anything.