Implications of missing this step?

[Michael D. Norwick]

Good Day;

Running PC-BSD 8.1 with a custom kernel and new world.  I just finished 
another custom kernel and rebuilt world according to the FreeBSD 
handbook.  While reading the docs again to find an answer to a question 
about how upgraded ports are handled, I came across the following in 24.2.3;

"If a custom kernel is in use, the upgrade process is slightly more 
involved. A copy of the GENERIC kernel is needed, and it should be 
placed in /boot/GENERIC. If the GENERIC kernel is not already present in 
the system, it may be obtained using one of the following methods:"

I am in the process of doing #>portupgrade -af with a new custom kernel 
and stock (rebuilt) world i.e. buildkernel KERNCONF=KERNEL_011911, and 
buildworld... (after upgrading src and ports with csup).  Things seem to 
be going ok but the statements about 'old object files and libraries' 
being out of date for third party applications, make me feel as if I 
have done something wrong.  I blew away the GENERIC kernel several 
iterations of kernel builds ago.  I always start a build with #>make 
clean.  What can go wrong by not following the above step?  Is a GENERIC 
kernel always needed?
Thank You,
Michael