Hopefully Al R will see this, as last I knew, he was still looking for this variation.
The line on the Aaron has always appeared to me to be much lighter than the line on the Boswell card, plus as mentioned, the lines do not appear to cross any borders, so my guess is that they are unrelated.
In other cases where lines continue from one card to another, in most all of these cases, the edges of the cards are crossed by the line.
post 240
http://net54baseball.com/showthread....187722&page=24