Yep, they are just text.
On my forum, the only users who's names show up in color are the Mods/Admins and we are both in green. All other users are in default blue. So, I make buddies show up in a different color in the forum users list by changing the template "forumdisplay_loggedinuser" (color2 is a class I defined in my css):
HTML Code:
$stylevar[dirmark]<if condition="$loggedin[userid]"><if condition="$loggedin[buddymark]=='+'"><a href="/forums/member.php?$session[sessionurl]u=$loggedin[userid]"><span class="color2">$loggedin[musername]</span></a>$loggedin[invisiblemark]<else /><a href="/forums/member.php?$session[sessionurl]u=$loggedin[userid]">$loggedin[musername]</a>$loggedin[invisiblemark]</if><else />$loggedin[musername]</if>