4BSD license issues

[markucz%gmail.com@localhost]

Hi,

I have some trouble to understand what the current legal status of 4BSD is.
According to Marshall McKusick (http://www.mckusick.com/csrg) one can obtain
all BSD releases *without* having to pay for a AT&T license:

> As of January 2002 you no longer need a license to order these CD-ROMs.
(i.e. the CSRG Archive CD-ROM set)

Does that mean one can use and incorporate e.g. nroff from 4.3BSD in a
software product of one's own?

If this is not the right place to ask such a question, I'd be grateful if
someone would redirect me to an appropriate mailing list.

Thank you in advance.