It's 1964 and it only appears on the Obverse side on the Lincoln Cent Mint marks were hand punched into the Obverse Die that was used to strike the Blank Planchet in 1964. So they are found in different locations under the date.. sometimes even almost touching the date.
Yes.. the Hand punched mint marks were struck into Cent Die I believe until 1989 When the Mint mark was punched more than once you have what is called a RPM - Repunched Mint Mark I want to share this webpage with you - http://www.lincolncentsonline.com/rpm.html
