Puzzle Bobble 4 ERPOM changed question

[XtraSmiley]

So I recently purchased this PB4 and I noticed it has been opened (the tamper sticker is torn off), so I took a peek inside. Looks like an EPROM has been re-burned. Then I noticed a gold sticker on the label. Clearly some type of change to the EPROM, but if it was factory, likely they would have re-applied a security sticker, I would think.

Has anyone seen this before an any idea what's up with this?

 

[truxpin]

I doubt it was done in the factory but i am guessing it has been region swapped as the eprom that has been tampered with is the one that usually contains the region byte