For better or worse, Outlook 2007 shipped with a lot of printing bugs. One of the more notable and annoying drops days and rows when printing multiple calendar months.
Whether or not you should install SP1 is an iffy subject. I’ve done so and have nothing bad to report. Others haven’t been so lucky. In particularly, SP1 seems to cause problems with Exchange, but if you’re running Exchange, somebody else is probably making the installation decision for you.