I think I can narrow the date range down some. It's 1959 to 1982. (You can see the faint image of the Memorial building, and it obviously isn't plated zinc.)
Send to PCGS for authenticity. Might not get slabbed. If it not slab, send to NGC for slab. If it no slab again, send to ANACS for slab. Coin need slab for most resale. Me promise you this best for buyer and seller. All Win in transaction.
I have to disagree with all of you. I think it came from the mint like that. It appears to have been struck through sand. Somehow sand got on the press before the planchet arrived. Then, when the planchet was in place, more sand somehow got on top. Then, when the dies came together, the sand was pressed into the planchetf on both sides, making the rough surfaces seen here.