The kernel source is exactly the same regardless of which processor you are using.
If you ever compile the kernel, one of the first things you do is to choose the processor version, which selects out anything not relevant to the given processor as well as telling the compiler which CPU to make code for.
x86 things are not the same. Anything compiled for a 386 will work on a 586 — but not the other way around. And messing up the kernel is one of the few things that can
really leave your computer in a mess.
If you've got the time, it may be worth installing the latest kernel source from
www.kernel.org and compiling it; that way you'll know that you're running the latest kernel and that the kernel source version matches the installed kernel. Instructions can be found at
http://www.projektfarm.com/en/suppor...l_compile.html (for Debian; you'll find more instructions through Google).