You are right. There are so many variations. Biggest difference, is the stamping. The ruler, SOG logo and the handles are very crisp, they are most likely made in the US. Also, if they did not come with gear covers, they are made in the US. The sure way is if it says made in the US stamped on the tool or if the paperwork that comes with it says made in the US. Hex bolts or Allen screws hard to judge by because they seem to keep switching back and forth.
Hope this helps.
Nate