Jack Daniel’s is filtered through sugar maple charcoal which both mellows and imparts flavor and therefore cannot be labeled a bourbon. Bourbons are filtered through activated charcoal, which is very different. It imparts no flavor but just removes small particles, as if you put it through a Brita pitcher. Thus, pretty much all American whiskies are charcoal filtered, but very few use the “Lincoln County Process” of Jack Daniel’s which adds flavor. So any similarities you find between Black Label and Old no. 7 are not from the filtering process.