^ That whole KAL/Proamerica thing remains somewhat a mystery on its own. Toss in JS Technology and you'll be scratching your head for sure.
I have at least three ProAmerica 1/4" drive sets, and (unless I'm mistaken) a couple KAL branded sets as well. The contents are identical - they were packaged as a "small arms repair kit" with an NSN number on them.
If I had to put money on it, I'd say Proamerica was OE for JS on SOME items. (NOT all.) I know for sure they're OE on Jensen (per a phone conversation with Jensen a few years ago) on the 1/4" drive socket sets, and OE for Proto and Tekton on some models of pliers. Those I've spoken with on the phone at ProAmerica were unfortunately a bit reticent about divulging who their other contract accounts were.
(And KAL produced in Japan is of course going to be a bit different than domestically produced KAL.)
(And in an attempt to clarify: KAL is still a viable entity on its own, unless I've been misinformed. 100% of KAL's production is contract stuff for military/government. Proamerica (KAL's "sister" company) is the brand sold to the public, but (from what I understand) most of their production is done for private-label contract accounts (Proto, Tekton, Jensen, etc.)