Optional automatic transmissions offered behind the 444t?

I admit I am not a trucker but who better to ask for my question. I have been thinking about installing an Allison automatic behind a 7.3L power stroke. I have located the proper SAE bell housing and adapter for an automatic from a444 but I would like to know what was available from the factory during the 444t run. All I have seen for autos so far are 545s. Could you get a 5 or 6 speed Allison in the later year trucks equipped with a 444?