I don't agree. If you are running FreeBSD version 11.2, then the cp
utility (just as an arbitrary example) will be version 11.2, and its documentation will match the result of running "man cp" on the machine, and will match the man page on the FreeBSD web server for that version. They do not have their own version number. There is no possibility of confusion, unless you deliberately replaced them, or built your own system from modified sources (in which case all bets are off anyway).
Now, some base system utilities do have their own individual version numbers. I just picked a random example: ntpq
reports itself to be "4.2.8p11-a (1)" on my 11.2 machine, whatever that might mean. And clearly it is different from the version of other programs, like svnlite is "1.9.7 (r1800392)", whatever that might mean. You have to trust the people who built the base system that they matched the correct version of executables and man pages.
Yes, in FreeBSD the base system is a single "package" or "installable" or "repository", with a single version, which is easy to determine using freebsd-version
.