That is, if the Lincoln Cent Resource is correct (no real reason to doubt them; they know their stuff), how the MM is supposed to look. It's the Ball Serif version of the MM known for that year. http://www.lincolncentresource.com/San_Fransisco_Mintmark_Styles.html
Take this as you will, but I thought you may find it interesting... http://www.doubleddie.com/58306.html