It looks as though there was a transition during 1972, perhaps in line with Pre to L updates?
The V406 is a 71/72 color (Ditzler 14314) and the later 72 color is the Ditzler 14622. There at least 3 distinct shades of Grabber Blue, none of which have a Ditzler/PPG code matching De Tomaso.
But if you have found your oem color and have it mixed to match sounds like you are good to go!
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