Recovering base system files after failed installworld

[Alejandro Imass]

Hi,

I tried upgrading from 6.2 STABLE to 7.3 RELEASE, and everything went
very smooth until I rebooted the new kernel. Make installworld failed
complaining that cc1 was not executable. After a lot of tests, I came
to the conclusion that the new 7.3 kernel had some sort of problem
with my gvinum partitions, since executables were mysteriously
becoming corrupt and the miraculously fixed after reboot. So I
reverted to the old kernel and the system booted without any problems.
I reverted with csup to 6.2 STABLE sources, but now I realize that
some binaries of the base system were modified by the failed
installworld. For example, it seems that libc.a is not compatible with
the compiler as I now get:

/usr/lib/libc.a: could not read symbols: Malformed archive

Now, the question I have is: is there any way to revert all system
binaries to 6.2 STABLE without a previous backup? Can a utility like
freebsd-update help me restore these binaries?

Thanks in advance,
Alejandro Imass