Mary Cornwell Craig Memorial #19875654 has the death year left off, probably because it was partially obscured in the photo of the marker.
I believe I have found her in the SSDI: Mary A Craig, b. 27 Dec 1920, d. 27 Mar 2005; last residence, Detroit, Michigan; SSN issued in Michigan. The dates match yours exactly and supply the last 2 digits of the death year.
This information matches additional sources I have found, such as her birth record, which will allow us to link her with her parents, who are in the same cemetery. I will put them through the find-a-grave system (as suggested edits) after you have time to look at this message.
Photo Requests Angela, thank you so very much for fullfilling my requests for 3 photos at Camp Group Cem, Bienville Par, LA. I appreciate your generosity in volunteering you time and efforts to help those of us that live too far away to visit the graves.