I've been reading about rare 1964 SMS pennies. I know its a slim chance to find one but This penny stands out a lot. Very shiny and unusual color, it is very thick and detailed. It is also missing the Lincoln statue inside the middle of the Lincoln memorial on the back of the coin.. it may have been worn off but there's no evidence of one being there.
What you have is an ordinary, very worn circulating coin.
The effect is somewhat pleasing and is called a "circulation cameo" as a play on the ordinary cameo which happens to an uncirculated (mint state) coin struck on dies that self polished in use to make a very smooth field (the part of the design that isn't letters and Abe).
Circulation Cameo happens when the coin picks up a lot of ordinary dirt and grime in use, then continues to circulate and the high points (Abe) get worn down back to shiny metal.
It's a pretty effect on an old Seated Liberty coin. Here it's just fun.
That light, shiny pinkish color you're seeing is not natural. This has almost certainly been cleaned. An acid, like vinegar or soda, was probably used. This is not a natural cameo affect from circulation, IMO. Just worth a cent.