C7DF-V identification number is listed for this application in the shop manual, page 10-103 with the following caveats: automatic transmission, "late production". Late is not identified here. "Early" production lists "C7DF-H or C7DF-N".
In the 1960-1968 Master Parts & Accessories Catalog (MPC), section 95, page 5, there is a cross reference from the identification number to the service part number. That may or may not help. The C7DF-V service carb is C7DZ-9510-H. On page 14 there is a vehicle application chart that lists the -H, -N, and -V variants. However, they are all grouped together as equivalent, with a common service replacement. No notations to provide a clue as to early vs. late.
The only other thing I can add is that my 67 SJ C-code from December 1966 has the C7DF-V, and the date code aligns.