In short, yes. But, when I recent customer requested documented reference to that fact prior to canceling a subscription to another inventory solution, I had to go digging – deep!
What I was able to find is the True Up Guide on Microsoft’s website.
Page 3 of the document confirms that indeed you may use several of the built-in reports to support your True Up efforts. While it’s a little dated and references SMS and SCE, it’s well understood that it naturally would cover ConfigMgr as an inventory method as well.
Here’s a link to the guide for your reference:
P.S. Make sure you’re using a service packed version of ConfigMgr as the their were issues with the RTM release that showed free Office viewers programs as the full products in the earlier reports. This issue has been resolved in SP1.