I've been involved with 69s for 30+ years and a couple years ago I finally saw one, with remains of an 06A car. General concensus is it was a late addition [May-June 69] no matter the 10-31-68 date in the AIM. I know of several very nice original Z/28s without it.
I took photos but the bracket is too badly weathered to determine original finish. The car has been outside since 1978.