The gas cylinder manufacturer is not the same Samhongsa that produced brass trains for Hallmark Models (not the card company), Pacific Fast Mail and others, plus diecast metal and injection molded trains for MTH, Weaver and others.
The office supply company has been around since 1970.
SAMHONGSA CO.,LTD
https://www.linkedin.com/company/samhongsa-co-ltd
The model train company was succeeded by another.
http://www.sammodel.com
Weaver produced the Alco C628 and C630 and the EMD SD40-2 before that tooling ended up in the hands of MTH. I’m not sure about the nature of that transaction. Regardless, MTH continued modified versions of those locomotives later, long after Samhongsa itself was no longer involved.