nfs, buildworld

[boxend at swbell.net]

I have 2 "slow" computers running freebsd, I have setup nfs to share 
/usr/src and /usr/obj from a faster computer with the two slower.
When updating is there a need to buildworld on the slower computers
after buildworld on the fast? I think not, I have been skipping the buildworld,
I build the new kernel (custom kernel file for each), install kernel, then installworld on 
the slower computers, without errors.  The /etc/make.conf files are identical on the 3 
computers.