57 part ID help

I removed that held the sparkplug separator to the lower passenger side of the block. 3/8"-24 x 1 3/8". Bolthead has the letter C underscored in raised letter on the right side of the bolt. Also attached to the bolt was a thin brass tag 1" x 2" with the numbers 126814 stamped on one side and 3 holes of various sizes punched in the tag. Is this brass tag something original? P1010003.JPG
 
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