Lizzie,
please feel free to use it.
I was very surprised to find it at a thrift too Dorthea's Closet (I know I knew your name at one point, sorry.) but believe me, it was Waaay more than I ever spend at a thrift. They knew they had something special.
Just an update, I contacted Valerie Steele, the FIT curator and author. She told me she couldn't disclose how much the museum paid for the coat or appraise it, but offered some museums that might be interested in it. I might contact some auction houses as well. through blogging and writing, I made some contacts in NY. I will keep you posted.
Thanks everyone for your help with this.
Sandra