From the "Mustang Production Guide, v1". 6F08C152006 has code 26A listed (date 11L), 6F07A152918 has code 25A listed (no date), several others. Also 6T07K163665 has code 66A listed (date 03M), 6T07A172616 has code 66A listed (date 18M). Many more in January 66.
(Date codes shown for reference.)
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