Principially it is like you say, and mostly male ornaticauda are easily to be recognized as such. I can only hope that your animals which are rather young and weak (after having suffered by that illness before) will recover and get stronger by the good conditions they will finally find in your tanks.
The exporters and importers know very well that they can sell many ornaticauda at rather high a price since the fish is highly wanted but a rare offer in the trade. They catch the new generation as early as possible in order to have an advantage compared with fellow-traders; and that means the fish are very young and by no means fully developed when they get in the tanks of the traders. They easily get infested by Oodinium and are further weakened by bad or no food, bad crowding conditions without shelter and often wrong water. Hundreds recover, but other hundreds (thousands) do not. I think that yours will because they have survived until now, but it is always a risk.
In ornaticauda there is a spectacular normal sex difference in colouration as it is in most other Paro-species. But the striking thing with this species (and parvulus) is that there is a singular change of colouration in the course of display in the breeding mood: the female suddenly adopts the striking colours of the male, including that “red flame” within the caudal. This is one of the reasons which lead me to suppose that these two species do not belong to the genus Parosphromenus but are rather “Para-Parosphromenus”.
But you should (and hopefully will) experience the normal sex-difference in colouration first.