Default CyanogenMod and official kernel sources

Hey,
Can you explain me one thing?

Does CyanogenMod require any special modifications in kernel source to compile CM?
Let's say that I have Device X from brand Y

and brand Y released official kernel source for my deivce x,

Do I have to modify kernel's source (the one brand Y released) before I use it as kernel source for CyanogenMod?
I have forgotten how does stock rom look like ^^