This is from 2006 bulletin
10. On the last down of a period, a Team B personal foul occurs during Team Abs touchdown play. Enforcement on the succeeding kickoff is the Team A choice. Ruling: The period is not extended for a meaningless free kick. The penalty is enforced on the first play of the next period which will be a free kick. Note: If this situation occurs at the end of period four the only choice is enforcement on the try. (10-2-2-g-1).
Is anyone aware of anything that supercedes this and says to go ahead and do the "meaningless" KO?