As one Vendor who sells figures (all legitimate) I to am wondering what figures you purchased and if you remember what vendor you got them from.
While I wasn't able to check out everything at the show, I do know most of the Vendors that were there, and know none of them sell bootlegs.
I know one thing not mentioned on the Good Smile website is that if the figure was distributed in the U.S. by one of the major Anime Distributors (AAA Anime for example) then they will usually put a label on it. In some cases it will also have stickers for the U.S. licensor of the Anime the figure is from.
For example, I currently have several Attack on Titan Figmas. Because I got them from 2 different Distributors, they each have a different sticker on the back saying where they are from (in this case AAA Anime and Ultra Tokyo Connection.) They both also have a Funimation sticker on the front since Funimation is the licensor in the U.S. Both AAA Anime and Ultra Tokyo Connection are official distributors for Good Smile and get their stuff directly.
While some Bootleg Manufacturers will try to duplicate the original Japanese packaging, it’s very unlikely that they would add these stickers. The presence of these stickers would be a very good sign that the figure is not a bootleg. Of course, some Vendors get their stuff directly from Japan so the lack of these stickers doesn’t necessarily mean the figure is bootleg either.