I good soul with access to QFHS gave me that info:
Mabel Emilia (Amelia) Anderson died 1942-05-05 and the govn't as her date of birth Feb. 12, 1883. She was living in Montreal at the time and the name of the next of kin was listed as Mabel Emilia M. O'Gorman. (she should be the daughter of Dickson Anderson and Blanche Cox)
So we are talking about 2 Mabel here.
I know that Mabel Amelia Mary Anderson married Constantine Alfred Woodward O'Gorman on Nov. 1, 1913, St. John Evangelist Church in Montreal.
So the 2nd Mabel would be born between 1914 and 1918 (death of Constantine O'Gorman 1918 in Ontario confirmed). When did she died?