Another image on my 1964. Upon getting it in hand it doesn’t look like a standard business strike but also doesn’t have the proof shine. While I highly doubt it’s a true SMS, it’s what the surface most closely resembles.
It looks like a proof to me! Are there any die markers for the 64 SMS? Compare your coin, especially the rims, to my toned 67 SMS. Business strikes do not have rims like this, they are rounded.
Decided to improve my storage this weekend and discovered my 1957 mint set (in a crappy holder)has toned even more. These are multi-layer protected with desiccant - still toned more. Decided to pull the cent and put in an airtite, it's color is maxed out IMO.