I'm doubting that the quilt in the picture is of mid 1800 fabrics because I'd venture that cottons of that era would likely be dry rotted from being stored in an non-insulated attic for so many years. The print could be from the early 1900s, too, but that also is quite old and could be damaged from being stored so long.
So, the fact the quilt didn't disintegrate makes me think it's younger than it appears.
Jan in VA