Here is the anti-spam configuration on an Exchange Server 2007 RTM server:

[PS] C:>Get-AntispamUpdates   

UpdateMode                  : Automatic
LatestContentFilterVersion  : 3.3.4604.600
SpamSignatureUpdatesEnabled : True
LatestSpamSignatureVersion  : 3.3.4604.600
IPReputationUpdatesEnabled  : True
LatestIPReputationVersion   : 3.3.4604.001
MicrosoftUpdate             : NotConfigured

And here is the same Exchange Server 2007 server immediately after upgrading to Service Pack 1:

[PS] C:>Get-AntispamUpdates   

UpdateMode                  : Disabled
LatestContentFilterVersion  : 3.3.4604.600
SpamSignatureUpdatesEnabled : False
LatestSpamSignatureVersion  : 3.3.4604.600
IPReputationUpdatesEnabled  : False
LatestIPReputationVersion   : 3.3.4604.001
MicrosoftUpdate             : NotConfigured

The Service Pack 1 installation disabled the Anti-spam engine updates. This stung me on a production system that I upgraded shortly after the SP1 release. Eventually someone in the office mentioned the ever increasing volume of spam emails to me and I subsequently made this discovery.

Sadly the Release Notes do not seem to include this issue.