Yes, this down is played by the rules of a try down, including point values, but is, in fact, a possession “series” in the Extra Period, and would follow 3-1-3-e & f. If team B scores other than on the try, game over. A little hard to arrive at that destination, but the path is already there, in the rules, as they are.
(Calling it a ‘series’ is linguistically inaccurate, but there are worse things in the universe. 🙂)