From what I can tell, the paper was purchased in 2008 by National Archive in DC. I do not know how it was stored, but I figure it was stored properly until it was sold to private party as surplus inventory a couple months ago. I believe it was then stored in a large commercial warehouse for auction.
Also, since I used the cut sheets from both top and bottom, any fogged paper should have been captured. For 15 sheets of 5", it is about 6 feet into the paper. If there is any light exposure, it should be contained within the first 2-3 feet of paper.
I'll play around with color balance. Now it looks like it needs some red color. Overall it has a cold tone to it.