Those holes were factory-drilled for the lower attachment of the RPO V31 Front Bumper Guards; if V31 wasn't ordered, there were no holes. G31 was Special Rear Springs and the tall rear bumper guards with the rubber inserts, which was included in the Z/28 package.Thanx for quick answer John!!
...but I could be possible that a X44 had this option you think?? ...or is it more likely they have been mounted as an after market option??