From the factory GM sets up the airboxs to silence the supercharger whine. And if the gauge doesn't read any boost that is grounds for getting them to bring the price down period. If you plan on buying the car fix it your self and keep that price down. If they fix it, you just lost some leverage you could have used to work them down on the price.
Just a funny thought... Did you check to see if the belt was on the supercharger? I remember someone on this forum finding a used car dealer that was removing the belts from the */C cars because he thought they would get better gas mileage.
1998 SSEi The Executive Hauler
Built Trans w/ 3.29s, P&P Jenny 5, S1X cam, Silver TOGs, Northstar TB & LQ4 MAF, FWI, Dyno tuned, #60 injectors,Oil Pressure Kit, 2.9-3.4MPS, MagnaFlow exhaust, 3" HF cat, MSD Coils & 8.5mm Super Conductors, AeroForce, only Sunoco 94, 100