I installed my own light bar, and you don't drill any holes there. The holes you drill are behind the inside side panels into the tower that the seatbelt is mounted to. I think these holes were used one of those body men who remove dents without painting. They do this by pushing dings and dents out from the inside, and need to drill a hole for access. I have seen that done, but the holes were plugged with a rubber plug. Or, they may have been used for some kind of door switch, maybe for an aftermarket alarm that was removed before selling it.