Assuming you're talking about EGR, locate and inspect the emission certification label in the engine compartment. It's probably on the upper radiator support. It will have abreviations for the installed emission control devices such as TWC (three-way catalyst) and EGR (exhaust gas recirculation).
If your car is equipped with EGR, the valve is on the rear exhaust manifold. If your car does not have EGR the pad on the manifold for the valve will be easily discernable, but it will not be machined.
I believe CA certified 103s had EGR in '89, but maybe not all, and I'm not sure about 49 state models. My '88 CA certified 2.6 does NOT have EGR.