I am beginning to resent K1000's suggestion that I have not "been around" in this hobby. Just because I haven't been on this site until recently or attended any of the gas bash rendezvous is not an indication of how long I've been collecting. I'm pretty confident it is longer than K1000. And that doesn't mean I don't have some experience in detecting fakes. I'm really not that interested in the opinion of one who touts that he knows his "****" if for no other reason than he chooses to uses language like that to establish his credentials.
As for when repops began:
I don't actually recall seeing any gas and oil reproductions until the very early 80s, maybe the very late 70s. That's when the globe inserts started coming out as well as a few porcelain signs.
I don't know what kind of Korean or Japanese repops you are talking about, Mr. Richards, but I doubt they were pump plates, globes or even gas and oil items. And you win the prize for being the oldest collector. I've only been at it since 1968.