Yes, judging from the pattern, it is that 47tile format. Because it is marked as free, you don't have to delete it as long as you don't share it in other places.
Oh, for the wall autotile, it will be weird and looks incorrect! This because unlike fences, RPG Maker technically treat a wall as vertical object and only span the full wall pattern horizontally. The upper part should comply with the 47-tile format though, but I don't think you will ever need that.
I will address this for the next update. Thanks for the feedback!
