Since there is such a wide assortment of fabric designs then you can add to it without effecting the look.
If you want to be more accurate and don't have the stash, then look in antique shops for fabric. Very often the booths will have rolls of fabric left from dressmaking.
It appears to be left from dressmaking or other clothing. I would date the overall look to probably in the 1950" even there might be fabric from prior years.