Can anyone explain why the following occurs?

$ sysctl -n hw.model
Intel Pentium III (Katmai) (686-class)
$ cpuflags
-march=pentiumpro

I looked in the cpuflags script, and even tho the output from sysctl matches
two possibilites in the case statement, by my understanding the output from
cpuflags should still be this:

-march=pentium3

I know theres not much difference, expecially on a headless machine, but it
still bugs me.
Thanks in advance for any insights
-dh