Yes, I can imagine someone speaking 15th century Japanese because of this advice. You'd have to be extremely careful of the film because they often don't sound like real Japanese, only real Japanese slang.
I agree. If you are learning Japanese, don't watch Samurai movies as your learning tools. Your Japanese would be so out of whack with the majority of Japanese people. I can tell you Japanese people don't tell you that (ie. you learn Japanese from Samurai movies) if you look un-Japanese looking.