There was a small window of availability for D96 Fender Striping on a Z/28. An update to the Showroom Album dated September 12, 1968 states:
"FENDER STRIPING (RPO D96, Body-side accent stripe) included with Rally-Sport and Style Trim Group. Not available with Sport Striping (SS or RPO D90). Available in combination with Front Accent Striping (RPO DX1) or with RPO Z28."
I interpret this to indicate is D96 was now optional with Z/28 or DX1 and Z21/Z22, no longer included.
This insinuates some very early production Z21 and Z22 Z/28s were built with D96. June 2014 there was an early production [mid-September '68] Z/28-RS on ebay. The car was rough and had a poor repaint early in its life. The repaint had mostly flaked off and D96 striping was visible.
Guessing here, I'd say Z21 & Z22 Z/28s included D96 striping for a short period of time. Per the Showroom Album Revision, D96 was no longer included but became optional as of late September '68. As a discrete option, D96 is rare, 5,176 cars. At some point, possibly the January '69 revision, the one stripe per car restriction was put in place.
Based on my db by the end of September '68 only 600-700 Z/28s had been produced. Of those about 58% had Z21 or Z22. That's about 400 cars; maybe a few more were also ordered with D96. Small wonder I have never seen an OE paint Z/28 with D96.
In conclusion, best guess D96 on a Z/28 with Z21/Z22:
August-September '68 probably included
October '68-December '68 optional but very rare
January '69 to the end of production-no longer available.
