One piece of evidence uncovered was that the nails used by Madison’s carpenters in ca. 1812 were rectangular, machine-cut nails and not the round, wire-cut nails used in the ca. 1901 renovations.  Because the different nail shapes left differently shaped holes, the nails and nail holes found in the ca. 1812 trim could be matched to the ca. 1812 nail holes seen on the surviving ca. 1812 nailers.