the sources seem to be in conflict, with one (the Patch) saying that the 30 Front St. property just sold was their last holding, and another (YIMBY) reporting that "The Witnesses still own two small properties at 80 and 86 Willow Street."
JW's like to when possible, rely on technicalities when denying or confirming an accusation - IF a response is actually offered.
While those two Willow Street properties may be located closeby to the former WT Headquarters, perhaps they are not considered or identified as part of the 'headquarters' properties the Patch article is written about.