Good luck with your Nova...my first L78 car was Forest Green also(36 years ago
).....3 things jump out:
CBS coded rear would have to be special ordered...the default rear axle for all the L78 cars was a 3.55 ratio and posi was an option, though most folks ordered it.
Next the trans code should be CW for the special high shift point TH400...the CF coded trannys were used in Novas, but I think the CF units were used with the L34 motors...
last item is the date on the cylinder heads...June of 69 seems a little early for a March 1970 assembly.
Please share some photos when you get her home...sounds like a nice car.
wilma