Grape has never been part of the 5 flavor roll.
Here’s a USATODAY report from 2003 announcing that the 5 flavor roll was being changed to raspberry, watermelon, blackberry, pineapple and cherry. Those flavors were chosen in a web-based promotion in which nearly 2 million people voted on their preferences.
Since 1935, the 5 flavors had been lemon, lime, cherry, pineapple and orange.
Here’s a record of all of the flavor combinations and packaging variations ever produced. It shows grape as having been packaged separately, but discontinued. It doesn’t say when the grape roll was discontinued, but several flavors were dropped when Nabisco bought the brand as a cost cutting measure, so grape may have been one of those casualties.