No, actually, he didn't. 
Any game in the clear cartridge was a GBC-only title. These began being released at system launch.
Pokemon Gold and Silver were games marketed for the Game Boy Color and designed to have color palettes when used in a GBC, but they were Game Boy cartridges. Note that Crystal has the clear cartridge - it's a GBC-only title.
Easiest way to tell is that the classic GB carts have a concave logo at the top, while GBC carts are convex. Also, all classic GB carts have a notch on top to fit in the GB. GBC-only carts do not have that, and do not fit in the classic GB.
Classic GB titles were made all the way into the GBA's lifespan - the last one was released in mid-2002. Obviously, therefore, the GBC's life didn't have a transitional period between it and the GB.
SW-5120-1900-6153
