Depends on how they are ordered, I take you have ones that are not. Your PM may have tried to save some money and took the low bid on the fixture package without realizing they were not whipped.
They are often times ordered prewhipped. They cost more but could actually save money because you don't have to spend time (labor) wiring them. I've heard some GCs say they have won a lot of bids after explaining the difference between the higher material cost vs the lower labor cost.