If your quilt is flannel with flannel backing; denim w/flannel, it will be plenty warm and I wouldn't use any batting.
I made a flannel/flannel/warm&natural and it is so heavy. My grands love it, but it is just too heavy (and warm) for me.
All this to say, determine its use and user as well as your climate, then decide if you need the extra layer of batting.
Suzanne