The VIP lounge where these keys were issued was in the court across from Terraza. Its door were not locked, so you didn't need a card key to enter. The main distinction between these and the keys you got from the main registration was that they served as a line pass for the coffee shop, Cafe Lago (which was recently converted to a buffet only). There was coffee and bottled water, but I was never offered anything stronger in the VIP Lounge so it wasn't a lounge in the usual sense of a bar.

The new VIP checkin is in the Augustus tower, also an open area not requiring a key for access. There's supposed to be a Diamond Lounge in the area for Harrahs Diamond players but I haven't checked it out yet. I'm not sure what the lounge next to Augustus registration is for. I'ts been there since the tower opened but I haven't gone in to check it out. That may be the one you're referring to that requires a VIP gold key to access.

By the way, there are several varieties to the gold room key.