Yep, as of firmware V10, all Model 3s (including SR/+) have access to Slacker streaming music, Spotify, Netflix, YouTube, a web browser, etc.
The community here is guessing that eventually those of us with partial premium interior will be asked to pay a subscription fee to keep the premium connectivity (most guess around $100 a year). But for the moment it's included.
Awesome, thanks for confirming. That basically sells the SR+ for me.