Can someone tell me how this got under the 6

Thanksinadvance223

What is this fam, i know it has the currency tracking study stamp although i cant seem to fathom how the 6 is overtop of the eagle let alone find a connectionbetween the eagle and the currencytracking study please help me

Greenstang

This should really be posted in the US & World Currency forum for best results.
To answer your question, it is just the type of ink used. Look at the green seal,
it is printed after the black but looks like it is sitting underneath.