In Webct format true/false questions don't have a special type, they are just multichoice single questions (:TYPE:MC:1:0:A). So currently they are imported as multichoice single questions with 2 answers True and False.
We should recognize them during import and import them as real Moodle truefalse questions.
My only concern is that I don't know if answers are always True and False or if they can depend on the language