The joys of knockoffs. :-) One of my favs is MC-10 Cassetteman, the original Soundwave. He has a bootleg of him that's so well done, it even fools some of the experts. :-)
The deal is, when you have two of them side-by-side, the differences are definately apparent, making identifying them easier. The real Cassetteman is blue, not purple. The manufacturer-stamping on the real one is Takara Japan, while the fake one is Shiantai Taiwan. Maz adds: "You can also tell them apart by the stickers on the knee. The real one says "Microman" and the fake says "Cassette".
Now *interestingly*, Gig in Italy had what was considered a Pre-TF release of Soundwave as well (note the headphones) but instead of it being cassetteman, it was actually the soundwave mold! :-) Hehe...