It would be worth sending in for PCGS' Restoration service. If it is not restorable then they will just grade it. If it grades higher after restoration it will be worth it.
By the way I sent one of my own a couple of weeks ago. I paid considerably more and hoping for good results.
I think from what I can see, better photos would be needed to comment on the authenticity and grade of this quarter. It will be very interesting to see results from PCGS. If this quarter is authentic and AU or MS as I think it could be, you should very happy with its value potential future worth. Good Luck
Fantastic find and purchase price....if its genine. I'm inclined to think the mint mark is correct. I have two of these myself and the depression looks the same, which is what you want. The only thing that bothers me about the mint mark is that in the original close up, the D look to be re punched (see my pic below)...I don't know of an RPM variety for the 1932 D. CPG doesn't list one. CONECA's first listing of an RPM for the Washington Quarter series starts in 1934 and Wexler only lists 1 RPM for 1932 S but no D RPM until 1935. This could be really cool, in that you found an RPM for a 1932 D Washington quarter, or really bad in that, at the very least, the mint mark has taken a hit which will always cause questions in the mind of your future buyer, and at worse the mint mark has been added, or augmented. If you send it in I want to know what comes back. I wonder if sending it to Wexler for attribution would be a good idea. FWIW my guess to the grade is AU53 tops, but because of being the key to the series, if it is genuine, you might get AU55ish. also looping in some known Washington Quarter experts... @NorCalJack @John Feigenbaum (if I've forgotten any one I appologize)
I know it's popular to grade coins from pics but it's also completely impractical. There's just no way to do it accurately. From the image I see the coin could graded anywhere from AU58-MS63 but it's also possible there are cleaning lines I can't see, etc. Not sure I love the mm either, to be honest.
AU53-55 tops,great buy for the price. If I had it would give it a dunk in PURE acetone to see if the crud will fall off or not.....
The only other thing I'll mention is that there should be a lot of heavy die polish lines around the mintmark. The second set of photos leads me to think it is most likely genuine.