812 Parts Index

Does anyone know anything about the "812 Index" referred to in the Engineering Changes? For example, on page 37, Section R, of the Engineering changes, the entry dated 2/1/37 states "The standard parts used with assembling this spring are shown in 812 Index, Page 82B, Lines 28-33 inclusive."
It would be nice to have a copy of this 812 Index to see exactly what is referred to in notes such as this.