Here's one of the links posted in that previous thread, I quoted one passage that stands out. As well, if you scroll down towards the end of the page you will find the White Rose fakes that are known.
http://www.wwcomponents.net/roseville/roseville.html"All pieces I have seen have "Roseville U.S.A." (usually very low relief on the USA) or "Roseville" on the bottom, even if they were not marked on original pieces. Initially, the Roseville fakes had a raised ("in relief") "Roseville USA" on the bottom. Apparently, U.S. Customs had a problem with that, so the ones being produced now just say "Roseville", with a space below that word where "USA" would have been.
The Huxfords' book lists the various trademarks that Roseville used. According to that reference, "Roseville" (without "USA") was used only from 1932-1937 and only as an impressed mark, never in relief. If a piece has "Roseville" in relief without "USA", I'd say that's close to a dead giveaway that it's a fake, particularly if there's an empty space where "USA" should be. On the other hand, the use of "Roseville USA" does not guarantee that it's authentic."
I'll let others more knowledgeable add their wisdom.