Yes there is a PCV valve. The PCV valve on GM 3.8 liter engines in on the passenger side of the car upper plenum in a well or compartment. This well has a pressure sensor on top of a 1/4 turn cover.Under this cover maybe a spring and two o-rings one on the cover & one on the PCV valve itself.Be careful don't break the pressure sensor, it also has a seal that fits into the PCV cover. The 3300 is a smaller version of the Buick 231, AKA 3800. The 3800 has no PCV valve. I could not find it either on my girlfriend's old Olds 3300. I think it's safe to assume that it simply doesn't have one. Go to a parts store and ask them to look up one. I'll bet they won't have it. The PCV valve sucks crankcase gases into the intake where they can be combusted. The valve itself protects the crankcase from becoming pressureized in the case of backfire which could cause lots of bad stuff. I'm assuming that the 3800 has enough crankcase "ventilation" where this wouldn't be a problem.
On top passneger side of motor. look behind the alternator inside the space down a little. was a pain to remove for me. On some models the PCV valve is located in the valve cover. A hose runs from the valve to the throttle body base plate or intake manifold. On other models, the valve plugs into the intake manifold and is connected to the valve cover by a hose.