If you are really buying the gun and your cousin receives it with the plan to turn around and transfer it to you, he may be violating federal law by certifying he is the actual purchaser (one of the questions that must be answered yes or no on the yellow ATF form). Buying a gun with the intent to transfer it to another won't fly. He probably would get away with it, but I don't think he'd be safe if the transfer was ever looked at closely. And you might be charged as well because you were part of the plan. If that transfer was allowed, in some states a subsequent transfer by your cousin to you would be allowed IF both were residents of that state. Since you are a resident of California and your cousin is a resident of Oregon, even if Oregon allows such in-state transfers without an FFL, the transfer would not qualify for the in-state transfer. I don't think an Oregon FFL can transfer to you in Oregon when you are a California resident, but I'm not sure about that.

As a practical matter, though, 451Detonics is right that irrespective of the federal law, the California law will probably get you if you take the Servicemaster from Oregon to California. Bottom line -- don't do it. Do like 451D says and keep looking for one in California.