Well, No actual hole drains like I think you are talking about. But water does flow easily via the channels in the floorboard. Even with the door shut it will exit fairly fast.
I noticed on mine that the rear footwell on the P4 has a few small holes for water to drain. I usually stop by the car wash for a good pressure wash when needed. Works well and no issues with draining.
What helped me on my last clean up on the P4 was to open up the dump bed, don't know what it's call. You can get underneath it and the passenger floorboards are right there.