disi, I have also been very interested in the 496 line pairs, pairs and the 496a variety. I purchased over twenty pairs. Many that I bought also have this heavy inking in the center.
This is one example.

This example I submitted to the PF as a "Scar on Washington's Neck" variety.

This was stated on the cert.
"JOINT LINE PAIR, RIGHT STAMP SCAR ON NECK.
AND WE ARE OF THE OPINION THAT
IT IS A GENUINE SCOTT 496, BUT DECLINE OPINION WITH RESPECT TO THE ORIGIN OF THE MARK ON WASHINGTON'S NECK, AND ATTRIBUTION AS A "SCAR", THE JOINT LINE PAIR WITH THE LEFT STAMP PREVIOUSLY HINGED ALONG THE PERFORATIONS AT LEFT, THE RIGHT STAMP NEVER HINGED. * * * * * * * * * * * * * * *"