Ahh...that's probably a dead drop or some other cutout designed to intercept and screen any mail she gets.
She screwed up, though, in thinking that her relative anonymity and her status as a liberal powerhouse would protect her forever from the "unwashed" hordes.
No it's not. It is her home address. See the link I posted much earlier in the thread - the one with the link to the Dallas Appraisal District.