IF it were MINE, I would not wash the entire quilt. I would fluff it on air in the dryer just to dust it out. I would try to get it appraised ...just for confirmation I guess. Do you have pictures of the quilt with anyone that can help to date it?
I would not 'hang the quilt' but I would drape the quilt over a rod or cabinet so it can be 'refolded and turned' every so often.....keeping it out of any sun light or bright rooms.
I love it!
Nan