You need orders to sustain a line, that said, as they were building a bunch of unassigned white tails you could argue the case to build more unassigned ones.
But one should imagine they had looked at the future sales possibilities before building the final tranche and determined the surplus amount they required. Whether additional ones would sell, now that's the question.
Though your problem may be if the final two are now on the line, suppliers of items already produced and installed may have closed their lines.