I recently acquired a "sample" version of Probotector 2 for the Game Boy and made a ROM dump. When run through MD5checker and goodgbx, the ROM is apparently different from the retail release. I repeated the ROM dump to double-check. However, in a quick play through the game a couple of days ago, I could not find any differences.

It is worth noting that Probotector 2 was released later than its North American and Japanese counterparts. The differences, if any, would be minor elements retained from the NA release, but have been changed for the final version. Still, I attached the ROM if anybody's interested.

Download: https://www.dropbox.com/s/hlqnznu73520739/Probotector2proto.gb

Here's a picture of the cartridge: