Not so sure that means it wasn't "Factory". American Honda published lots of stuff that was "Factory" sourced - Service Bulletins, Service Tools, Setup Manuals, and such. Since that was published in 1980, one test might be to check the threads used on this stand. If they are American National Standard (ANS), more than likely made in US. If they are metric, who knows? The sticker on that adapter doesn't say "American Honda".