It might be worth a phone call, but this looks legit, and it's not marked "upgrade" anywhere. You only get the installation CD, no books or other extras. For those who haven't dealt with them before, B&H is a highly-rated e-store
that's been around for over <strike>20</strike> 30 years.
<strike>$149</strike> $99 Vegas 6 link
One other thing to keep in mind: Vegas version 7
will be available around late September or so: read about it here
Edit: Vegas product info can be found here
Edit: Price cut effective Aug 24.