When you start receiving the incoming signal the format scrolls across the display. You also have the "Info" button below the display that will show the incoming audio format. It'll show any upmixing modes like you mentioned. If the incoming signal is a lossless format you won't be able to upmix as it's already the best available format.
Not sure about the surround default setting. I haven't used it at all, even though I've had my 976 for a couple years now.