wtf...I don't understand this stuff
My cman usa rethreader has a note inside the box (from Lang) stating its made in usa. None of the parts are usa-stamped except for the files. My jawco sets I'm guessing are exactly the same, but I don't have access to them to check. The Jawco files, which are in my Cman rethreader kit, clearly say "usa". It absolutely wouldn't shock me if other similar tools don't have COO stamps, because the paperwork is printed somewhere else.
The point is there's other stuff to worry about. Test them out before you throw them away.
$5 will buy you exactly 2pcs of 1/2-13 Grade 8 (nut, bolt, washer) sets from china. And that is bulk pricing discount at Tractor Supply these days (its $10/lb). In other words, to test those things, will probably cost you a couple bucks, but maybe its worth it?
Also so you don't feel like you got ripped off...? testing them out is probably good for your sanity rather than being bitter/mad about it...! And the community would benefit from real data rather than jumping to conclusions that maybe isn't warranted.