Ah, I figured it out. I took at look at pal.c and found examples via the default palettes, they are just simple arrays:
const u16 palette_red[16] =
{
0x0000,
0x0002,
0x0004,
0x0006,
0x0008,
0x000A,
0x000C,
0x000E,
0x000E,
0x000E,
0x000E,
0x000E,
0x000E,
0x000E,
0x000E,
0x000E
};