Unlikely (almost all the "rooftop koreans" had national service training in Korea) and unreported (that I could find)

  In the end, Chang said not a single person was shot and killed by the Korean shop owners — just warning shots to chase away potential looters and arsonists.

~ https://www.huffpost.com/entry/roof-koreans-meme-know-real-s...

Also, wikipedia: https://en.wikipedia.org/wiki/Rooftop_Koreans