User blog comment:Thegoldnguy/Pulgasari: The Lost 1962 Version/@comment-24277243-20151026124613

Found more info (thanks LMW).

http://kaijuphile.com/community/index.php?threads/obscure-kaiju-other-giant-monsters.804/page-10

The OP in this thread is the first person to bring this film to light.

http://www.koreafilm.org/english/db_detail_eng.asp?p_dataid=00803

And this link leads to the Korean Film Archive, which gives us quite a bit of info on the production of the film, and also gives us a synopsis of the plot:

"During the later years of Goryeo Dynasty (918-1392), a talented martial artist is murdered. His resentment makes him born again as Bulgasari, a monster that grinds and eats up iron. The monster takes his revenge on the traitors responsible for his death."