Excellent observation, and I am full of beans. As best as I can tell, there's no LED notification on this device.
If by chance you're rooted, there's an app available in Market, BlinkerTab, that lets you use bottom button backlights for notification.
There's another app that doesn't require root, NoLED, but I don't know if it works on Tab (it's for Samsung Galaxy S phones: close, but close enough?) and I've seen posts where people think it's hard on battery.