You probably already know this, but, a date code is stamped on an original bumper. That code is stamped on the down side of the chromed bumper just above the left turn indicator.
There is some adjustment available between the bumper and the fender. While the chromed bumper won't give you much if any the bracket can be persuaded to give a little and a little pressure on the fender itself will give you a little more. To get that 1/8" your looking for you will need to move the fender outward and bend the bracket toward the bumper. My experience anyway. Brian