While the ATF has released proposed new guidelines for "pistol" braces none have passed into law yet, i wouldn't get to caught up in the specifics just yet, the ATF released a draft that was set to go into law several months ago then at the last minute they withdrew it. I beleive they are testing the waters and trying to cause confusion before they try to pass anything official.

Jason, no Sir. Different style Braces will have different determining factors in a (point system) that will determine classification : nraila.org/articles/20210609/atf-targets-pistol-stabilizing-braces-in-new-rulemaking