It has the S mint mark. San Francisco only produced Proof coins for the Wisconsin Quarter. Check the rim to see if it's silver or the clad composition.
Thank You Thomas -- this coin has a mirror finish . This one I think I should have graded - an old friend gave it to me .
From your last photo IMO it looks like the Proof clad quarter. If a friend gave it to you just put it in a nice flip or capsule and keep it as a remembrance of your friend. It can be a bit expensive to have it graded.
From this last photo it does appear to be silver. I thought I had seen a copper edge on the upper right part of your previous photo. My bad.