I am not positive, but I think the PCBs are all the same regardless of the region (JP, US, or ER). The only difference is the sticker put on the cart, the manual, and the insert in the case. In fact, some of my US AES carts have "double" stickers where it looks like two stickers were put on top of each other. Perhaps the first sticker was for the Japanese version and then SNK decided to "convert" the cart to the US version by putting a US sticker over the original Japanese one, put it in a case with a US insert and US manual?