Reader ^ drew our attention to Marcott’s thesis (see chapter 4 here. Marcott’s thesis has a series of diagrams in an identical style as the Science article. The proxy datasets are identical.
However, as Jean S alertly observed, the diagrams in the thesis lack the closing uptick of the Science. Other aspects of the modern period also differ dramatically.
Here is Figure 1C of the Science article.
The differences will be evident to readers. In addition to the difference in closing uptick, important reconstruction versions were at negative values in the closing portion of the thesis graphic, while they were at positive values in the closing portion of the Science graphic.
I wonder what accounts for the difference.