I'm in at '64 but I suspect the 'powers that be' assigned it a '66 because of the craze of colour. (devil)
Wow, looks like someone tried to cut his jugular! Nice color, but the marks I'm seeing on the obverse limit this to a 63. And that's if it didn't get UNC Details, Scratched.
Initially presents as premium gem, but the marks on the lower neck and under IGWT should prevent that grade. MS65