2014 P Proof Kennedy Half DDO

Hi, I'd like some comments or opinions on some photo's of the coin. It came from a pre-ordered Anniversary set. I just opened it several months ago. The doubling 2014 P Proof jumped out at me. The eyelid has a ridge visible. I saw the ridge right off when I looked at the coin. There's distinct doubling in the upper eye, inside the socket. There's also doubling in other places. I took it to three coin stores in my area. The people from the store all agreed it's a doubled die. One offered to by it for 500usd. Has anyone seen or heard of other like this? I've never had coins graded so I'm not really sure about sending it off. I'd hate to lose it in the mail, or whatever. Thank you all...Paxo