You are ahead of yourself by a few years. Q3 came out in 1999, which means it was written in the late 90s, so think PSOne and late SNES/Genesis titles.

Aside from the PS2, I don't think so. N64 came out in '96, Dreamcast came out in '98 and PS2 came out in early 2000. In '99, we were only two years away from Xbox and GameCube. I know that at least N64 games were written in C.

PSX games were often written in C, as well. I suspect that developers had started to migrate to C near the end of the SNES era, although I'm not sure how many SNES games were written in C...

Playstation 2 had it's own devkit that was C or C++ I believe.

But yes, N64 games were written in assembler.