That was the 1st thing I looked at when picking up my rig after it was delivered .. Sales Manager was like, "what do you mean" .. I walked over to his new Limited and showed him why his rig was going to leak .. his rear tubes were wrong .. I would never have seen that myself if not for browsing these forums for months while waiting for mine to be built ..
After having the rig for 2 weeks, I decided to pull the carpet up after a really heavy rain .. took photos of the 2 inches of water and then we dug into the TSB's, Star Cases, etc. Mine stopped leaking for a bit, and we thought we had it .. but it started again. (Mine is in the front - so either the windshield comes out and gets sealed, or the fender comes off and gets sealed along the body seam).
Glad you caught yours and got it fixed!
Don't forget to also look at the 3rd Brake light just in case ..