//Are there any ABers who believe in the literal truth of the ark story?//
Not I, but there were certainly floods in biblical times & earlier. With one impending, it would be smart to move your livestock to high ground, if there wasn't any high ground ? - stick 'em on a boat!
These tales are very old & were told over & over again ( no telly you see) and grew in proportion & have been subject of many translations. Somewhere way back in the mists of time, something at the core of this story is based on a true event.
It's a great story though, when I was a child I loved it & made many drawings of it.