While a few are indeed sets there are some I can't recall seeing (such as the Information Center, which was probably too specalised to deserve it's own set).
As already pointed out the Pizzeria set is very similar to the one in-game.
The set "6598 Metro PD Station" was the in-game police station, incuding jail. The helicopter could be build during in a minigame in the police station. Accessories like the box of donuts and flaming pizza were not included in the set.
The set "6334 Wave Jump Racers" was the beach lookout where you could start the jet-ski race around the island.
The Lego race cars in the game were similar to these sets: 1477, 1990, 1517 and 1612. I can't find the racetrack start itself but it was in keeping of the Octan branding that was used.
I thought the ambulance was set 6666 but I was wrong, the one in-game had a much longer sloped roof.
The Bank (which was always closed?) I can't really remember anything along the lines of, and I think the houses up on the hill were just generic lego houses.