It is possible they were supplied with the faux chrome during the '68 MY, but not much longer. In my 15 years of ordering/selling parts, GM had no qualms at all about furnishing a part that fit and functioned but didn't necessarily look the same. A few examples:
When ’68 Z/28 chrome rocker covers were ordered they substituted ‘69 Corvette L79 covers.
When '69 BB chrome rocker covers were ordered they substituted ’71-up covers with the snap-in rubber oil cap and lousy chrome.
When a ’69 Camaro rear license plate bracket was ordered, they substituted the 73-up Nova bracket.
When ’69 Camaro 396 fender emblems were ordered, they substituted ’70 Nova emblems
When ’68-69 Camaro rear spring anchors were ordered, they substituted ’70-up anchors with the sway bar tabs.
When a ’67-’69 12 bolt axle cover was ordered, they substituted a ’70-up cover notched for a rear brake hose bracket.
The Aug '71 P & A manual lists only the '68 part numbers with a note.