I do not know if anyone has pointed this out yet but I think it is kind of funny/odd.

I was trying to find a connection to the 340 and was mapping out the placement of where I thought the "periods" should be. When I stumbled on the "Z".

If you take a pen and graph the spaces that do not have a letter (they were removed by someone) and draw a line through them—-the letter "Z" is revealed. And in addition they also spell out "I dot" or maybe "do it" when you replace the missing letters.

I just thought it odd that both sites that posted each of these images had the letters missing from the 408.

The Harden cipher solve— does not have those letters missing.