Why old files in /etc ?

[Michael Gass]

Just installed 7.2-release in an old Pavilion 4455 (PII, 256M)
and it runs great.  Csuped src and ports and rebuilt world and
generic kernel for 7.2-stable and that went well. 

My question is why are the files in /etc in 7.2-stable older 
versions (generally) than in 7.2-release?  I do not just mean
older by date, but older versions of the files - like many of
the config files for sendmail or the net.  Why  is stable using
older versions of these files than release?

Mostly I did not let mergemaster install the files from the build
because they were so much older than the original release versions.
Again, why are the files for stable so much older?

Thanks,

Mike Gass