Sorry for the massive bump, but I just felt like answering to some stuff in here.
Probably still fakes if you're 100% sure the numbers aren't there. There are many variety of fakes, even ones that look really authentic. All games should have the two indented numbers, even old GB games. They might be very hard to spot, try using some good light source.
Mega Man Zero is one of the few GBA games that do have a coin battery. Check this: http://gbatemp.net/threads/gameboy-advance-gba-games-requiring-batteries.322803/I just found out that the Mega Man Zero game I have is now fake. It has a battery inside it.
Both my Fire Red and Leaf Green don't have the number code indented onto the front sticker, but it is real cause I see that the chip inside is has two little small roms and does not have a save battery like the fake ones.
Probably still fakes if you're 100% sure the numbers aren't there. There are many variety of fakes, even ones that look really authentic. All games should have the two indented numbers, even old GB games. They might be very hard to spot, try using some good light source.
There are even fake Pokémon GBA games with shiny labels. Some fakes are easy to spot, others aren't. Best bet is to find an auction with a high-res image, often the "E" rating and the Nintendo logo are different on the fake ones.is the label shiny (hard to see in pic)
Wrong. There are several fakes with Nintendo above the cart pins, but usually the Nintendo logo is bad looking. It's very easy to spot a fake once you actually open the cart. Don't just assume a cart is real if it has no battery, but rather if it has all the various markings and the same PCB layout and so on.Here's my short guide on how to spot fakes in under a second:
If you look at the cart contacts, do you see "Nintendo" printed there?
If not, FAKE!
If yes, REAL!
As far as I'm aware, no bootleg cart in existence replicates the "Nintendo" on the PCB.
Don't forget the bad looking Nintendo logo (the font) and the E rating.They've been pretty common recently. The only distinguishing factors are the lack of "crystal" hologram on the front and (obviously) the cheap PCB.