Ihave a 58 chev fleetside small back window .Can someone tell me what the holes are for. I have 3 holes on each side of the rear widow they are in a dimond shapeand pattern about 2-2 1\2 inches apart .I am not sure if someone put them there or they were ment for somthing originaly .I will fill them in if they are not necessay .Thaks for the help