My car had Rock on inner fender wells. E body built 4 30 70 .I don't think this s a persons name .I think its simple nobody would spend time to just do something they were not told to do. I think it just stands for Rear Operators Checked. That they rolled the rear windows up and down and they worked. Just my opinion. We will never know unless the guy comes forward to tell us. Inspection marks make more sense than a worker wanting to sign his work of art