With the very expensive games reproductions seem to be pretty legit. Correct colours stickers as an easy touch sliding the cover in an original case of a cheap game Not to mention that the screws are covered by the cart lable how can you actually spot reproduction japanese megadrive games if they look identical even from legit sellers there is a chance that your getting a reproduction since opening them will not always been an option not to mention the potential to include reproduction manuals and box art wich look identical to loose copies of the game example of pulseman https://www.ebay.nl/itm/Pulseman-Me...252044?hash=item4b47a08f8c:g:FpIAAOSw0W5Z8vK3 A pretty nice example not to mention that I'm pretty sure while there are not many listed on ebay as repro's physical stores or collectors in the 2nd hand market could be selling those legit repro copies as legit ones if the quality is this good. The chip set would be the difference but opening them can be a pain without damaging the cart lable.
I think all you can do is compare against pictures that you know are of the genuine article. For instance, maybe you could discern that the printed quality of the manual or insert or label are not as sharp or otherwise look a little off, or maybe they have used a real megadrive cart and plastic box, but the plastic boxes came in different variations and perhaps they have used the wrong variation. Maybe you can ask for a picture of the cartridge contacts, which will show you the color of the circuit board, and you can compare that to the real deal and see if it looks different at all. Finally, consider where the item is coming from. If it is being sold from anywhere that is not Japan, then consider that perhaps it is not the genuine article. Many repros and bootlegs come from obvious places that are known as major sources of bootlegs for movies and games, such as China or Thailand, but in the neogeo scene at least, bootlegs are being made by folks in France and other European countries. If you see it for sale on an auction site or other website, maybe see if the seller is selling other stuff that is too good to be true, or search his completed auctions and maybe you will see he has sold several copies of certain rare games. When in doubt, maybe just try to source a copy of a Japanese game from a Japanese seller. If something is too good to be true, such as a rare $200 games selling for $50, it probably is too good to be true.
I've actually messaged a proffesional japanese seller hit japan about this Their answer being that they are proffesional as their answer , o well it's a good thing I'm probably not going to collect those high end japan titles since the very proffesional ones look identical. If the repro's look that proffesional 100% identical to the real thing except for the chip set wich will probably not be opened since the lable is in the way of the screws for the japanese carts, even from a legit seller you can be screwed if they do not even know the difference. as far as different cases go you could also swap cases if the original is broken so in that regard it could still be legit. Gamplay wise it's not a big deal everdrives or emulators are enough as far as gameplay goes. https://www.ebay.nl/itm/361865393403?ul_noapp=true
