Right, if a new topic is given, else display the topic.

http://www.faqs.org/rfcs/rfc1459.html
Quote:
4.2.4 Topic message

Command: TOPIC
Parameters: <channel> [<topic>]

The TOPIC message is used to change or view the topic of a channel.
The topic for channel <channel> is returned if there is no <topic>
given. If the <topic> parameter is present, the topic for that
channel will be changed, if the channel modes permit this action.