Ginger oil contains a vast number of terpenes, sesquiterpenes,diterpenes and other phenolic type compounds. What you are referencing is the active ingredient in the root ginger. Understanably there has to be gingerol in the ginger oil. The concentration would have to do with the manufacturer and how good there steam distillation was. I used ginger oil to elevate the levels of alpha-copaene and that goes from 1 to 8 percent.
The short answer is it depends. Im sure its there but exactly how much is a mystery. "Pure" ginger oil is a heterogeneous mixture of compounds any way. Nothing pure about it.