Good question... I downloaded the latest navigon maps to get the DEM file to hopefully get the 3d terrain view (i.e. mountains). So whether it's compiled by Navigon from NASA date, or compiled by Navteq, etc. I don't know.
This doesn't typically display like this on our units, does it? I have to admit - I didn't check before I updated it... But, in the driving that I've done before the update I hadn't noticed any actual terrain changes/topographic changes on the map. As mentioned though, the DEM file is huge... It's around 250mb for the US file. The Canada file is 106mb.