Originally posted by: BouncekDeLemos
Regular Gameboy game:
Despite the cart shells being the color that they are here in the west (Pokemon red is red, blue is blue, etc.), in Japan, they're all gray.
Any Gameboy game that's enhanced for GBC would be in a black cart. Much like the carts here, in japan, they're black.
https://i.imgur.com/0W39TfO.jpg
Pokemon Yellow is a gray cart
https://i.imgur.com/97LvaV7.jpg
HOWEVER... I need some confirmation...
Did the one we got here have enhancements? I don't own Yellow anymore to find out, and it could very well be enhanced over the Japanese version which is only a regular GB game (?)
If you stick a regular gray GB cart in a GB, GBA or GBA SP, you can get the option to change the overall palette. Can you do that with the NA GB game? This trick will not work with the already enhanced black carts nor the clear GBC ones, only gray carts.

Pokemon Yellow here has enhancements for the Super Game Boy, but not the GBC specifically; the GBC just uses the pallettes made for the SGB.