You used the right lounge. Signs we found called it a VIP Longe. We also used that one, twice, when flying US Airways biz class. My wife was happy, since the VIP lounge has showers, which US Airways clubs (even CLT) do not. The TAM club next door is, as mentioned, a "TAM Gold" lounge. We couldn't get into that. www.loungeguide.net calls the lounge you used the "Rio De Janeiro (GIG) Independent Smiles VIP International Lounge," and listed access as "TAP Portugal, United Airlines, US Airways, Priority Pass." Maybe it was a true Smiles lounge when the Smiles program was Varig's, as an independent airline (before it merged with Gol). Perhaps Varig still flies out of Terminal 2, though increasingly their planes seem to be painted over as Gol planes. Gol flies out of Terminal 1, so the lounge in Terminal 2 would not seem to be theirs anymore.

When CO and UA truly become one (sometimes in 2012; still a work in progress), I wonder if all operations will be moved into one terminal. Since they will all be called United flights, I don't see how they could continue to have two separate check-in desks, etc. Of course, many check-in desks are interchangeable (e.g., US Airways sets up shop in the early evening at gates used earlier in the day by others).

I think the lounge closes at 11 p.m. I don't know of airport lounges anywhere that are open all night. I imagine at least a couple of places in the food court, on the departures level of Terminal 1 (the one Gol and AA use) will be open in the wee hours, though the quality doesn't match the prices. We had a better meal in the Luxor hotel inside Terminal 1 (doubt it'd be open late).