DavidCB
No it's not, but it will be easily doable by affecting an ID and set this property with CallJS plugin. (possible directly with the native textbox object.)
if your textbox object has text_01 as ID,
Call (On loader layout complete) with the CallJS plugin :
var a = document.getElementById(""text_01""); a.style.textAlign = ""center"";
(Note. Double quote "" equal " in the expression editor.)