Getting latest files with cvsweb for a given tag

[RW]

Is there a cvsweb URL that will give me the latest version of a given file, 
given a specific tag? ie  without specifying a explicit revision.

What I am trying to do is write a script that will download the latest version 
of  src/sys/conf/newvers.sh for RELENG_6_0, so it can parse out the version 
information and compare it with the output of uname -r.

Or is there a better way of determining whether the  installed world has been 
superceded by a new point-release (aside from reading mailing lists).