Source code version

[Sreeram BS]

Hi,
     I have 2 questions related to source code of standard programs(commands) of FreeBSD. 

(1) Assuming I would like to get the source code of program 'tail', then I visit this URL http://svnweb.freebsd.org/base/head/usr.bin/ and enter the  'tail' sub-directory. Here I see the tail.c file, but there is a version number(revision-number) next to it and that is the actual link for the program. Now, this version number is different for different utilities. For example, the latest version of tail.c is 251565, whereas the latest version of another program, 'basename' is 216370.
    My question is, is there a common path which can take us to the latest version of these programs? For example: http://svnweb.freebsd.org/base/head/usr.bin/tail/tail.c?revision=LATEST ?

(2) Is there a way, where I can get the revision number of source code of a program shipped in a particular release. For example, 'tail' is present in FreeBSD9 and FreeBSD8 also ('tail' is present in all FreeBSD releases, and so picking that as an example). The source code for 'tail' in FreeBSD8 could be different from the one in FreeBSD9. Is there a way to obtain the revision number of tail.c program that was shipped in FreeBSD8 (or FreeBSD9).

Please suggest and inform.

Regards,
Sreeram