It appears you made a copy of GENERIC without changing anything. You need to open the file P200MMX in your favorite editor, and change the "ident" line to whatever you want your kernel to identify itself as. As far as the kernel and kernel.old being the same size, that's expected as you haven't change any configuration at all.
I suspect that if you type "uname -a", you'll see generic, but you'll also see towards the end something like:
Code:
root@<your hostname here>:/usr/obj/usr/src/sys/P200MMX