From my research over the years:

I believe in 1968 the headrest were a option you could add, but in 1969 they were standard due to safety.
The emblems are all standard on gts cars for 1968. The color depended on the color of your car.In 1969 If you had a stripe delete car you got the front fender emblem. If you had a rear stripe you did not get the front fender emblem.