After SP1 for Office 2010 is installed it is not directly noticeable that it was installed.
Below are a few screenshots of which you can see that SP1 is installed.
When you look at the version number, in this case 14.0.6023.1000, you will find no referral to a service pack level. To see this you’ll need to click on “Additional version and copyright information”. Now the help, about screen. This does show the Service Pack level.