https://www.immigration.go.kr/immigration_eng/1852/subview.d...
Doesn't look like it. Several restrictions on how many (max 5) dependent upon the construction budget.
If Korea selectively needs to bring over skilled workers, there are options. But hundreds?
No, it absolutely can't. I'm familiar with the Korean visa system, and you're correct.
"The L-1B nonimmigrant classification enables a U.S. employer to transfer a professional employee with specialized knowledge relating to the organization’s interests from one of its affiliated foreign offices to one of its offices in the United States. This classification also enables a foreign company that does not yet have an affiliated U.S. office to send a specialized knowledge employee to the United States to help establish one."
https://www.uscis.gov/working-in-the-united-states/temporary...
B1 is very restricted in the kind of work that can be done and it is claimed that the Hyundai workers have violated the restrictions.