The data plate came in 2 colors:
Black for M30J non-Acrylic Enamel & Gray for M32J Acrylic Enamel

Data Plate DeCode Tables/Charts

PAINT      TRIM      ENGINE      SPECIAL ORDER NO
Make Model      Year Drive     Consecutive Serial Number
Year will be 64 for all 1964 production
Drive will be L=left, R=right
Serial Number will be the actual consecutive vehicle number