A home built in the mill-town era was constructed before insulation was a design consideration at all. What is in the walls now was added later, by somebody, at some point, and it is frequently not what anybody would specify today.
The pattern we find repeatedly in older Somers homes includes attics carrying a fraction of current recommendations, with depth that thins to nothing at the eaves; completely uninsulated rim joists and sill plates where the framing meets the foundation; balloon framing that provides an uninterrupted air path from the basement to the attic; and batt insulation added in the 1970s or 1980s that has since sagged, compressed or been damaged.
The air leakage in a house like that is usually a larger share of the heat loss than the missing R-value is, which is why we lead with air sealing rather than with adding depth. Adding insulation over an unsealed ceiling plane gives back much of the potential improvement.