Leonki: Buyer beware? That's nesman85, he has been selling protos for years.

Some more information and history about that particular proto.
Leonki wrote: 1) Why would an opening be cut in the cart, when it's clear that the memory chips are soldered in place. I've only seen cuts where removable EPROMs were present.
That was how it was when I got it from Video Games & computer Entertainment Magazine. It's a review copy. I can guarantee its authenticity.
Leonki wrote: 2) Darkman uses an SLROM chip. It's clear from the picture that this is not a proto board, but rather a production board. If that's the case, then those are ROMs and not EPROMs (even back in the day, EPROM pinout was different from ROM pinout!)
I'm sorry, there are TONS of protos that use production boards. I'm not sure how many YOU have handled, but they don't all come on TKEPROM boards. Also, those are EPROMS, not ROMS on that board.
3) Seeing that these are ROMs, then why do they have stickers on them? There's no window to cover.
See above, they are EPROMS.