How to tell a bootleg portrait of pirates figure?

A lot of bootlegs are produced mainly by Chinese/HK counterfeiters. One reliable way to recognize official products is by spotting the little Toei sticker put on the figure box. However, collectors that got their figures from untrusted sources must still be vigilant as sticker faking activity is known to be true since late 2009 / early 2010. Fake stickers are easily recognizable because of their poor print quality.

Sometimes, stickers show a number on their top right corner. It may be an indication of the rarity of the figure: the highest number, the rarest figure.

Those stickers come into several flavors:

A golden or silver sticker with Japanese lettering shows that the figure was originally designed for the Japanese domestic market.
A silver sticker with English lettering indicates that the figure has been exported by Bandai for international markets (be it for remaining Asia, Europe or America).
The general consensus among fans is that stickers put on products designed for the Japanese domestic market should all have a golden background. That's why, although several kinds of stickers are put on official products, collectors prefer to search for figures with golden ones.
However, Toei stickers for the Japanese domestic market seem to appear following these rules:

For products below 5,499¥, stickers should have a golden background with black lettering.
For products in the range of 5,500-6,499¥, stickers should have a silver background with black lettering.
For products above 6,500¥, stickers should have a silver background with red lettering.
For instance, although nearly all POP figures do have the golden version of the Toei sticker, exceptions occured with all Neo DX and some Strong Edition figures released on the Japanese market, having the silver version as being the only figures above 5,500¥.
Despite these general rules, some people seems to still get a golden sticker with black lettering, as for Neo DX Kuma, a figure of 8,820¥. But those cases are rather scarce.
The same kind of rules should be applied for stickers on products for international markets. In this case, they all retain a silver background but with several letters coloring, as black, blue, red or even green.

Moreover, genuine stickers have their backsides filled with the Toei logo as watermark. But to check this, it requires to peel stickers off boxes.
Aside from the Toei sticker, other differences between official products and bootlegs may include differences in the box, lack in overall detail and taint/hue/depth in the paint on the figure itself. The bootlegs may be priced at the same price of the original figures or priced as a cheap counterfeit version for fans. Occasionally, they are sought by collectors despite being fake. The most notable way to tell a fake straight off is usually in the face as bootlegs are often less defined/detailed. One Piece P.O.P. also carry the Korean One Piece logo, the One Piece logo over a black flag, as they are intended for a wide target audience, a common sight on non-Japanese produced products. On the bootlegs, this logo may appear but often is poorly reproduced, along with the other logos on the box.

Finally, it should be noted that products exported from Japan by different companies than Bandai may not have the Toei sticker at all. It's generally replaced by other stickers:

Figures exported to the USA by AAA Anime Distribution should have both FUNimation and AAA stickers.
Figures exported to Europe by Abyss Corp should only have an Abyss Corp sticker, sometimes no sticker at all.