I am 81 and recognize this butterfly pattern. The time is correct from the looks of the individual fabrics used although the same pattern is still used from then until today.
The muslin is not tea dyed, It came that light beige color, and lightened with washing and drying it in the sun outdoors on clotheslines.
These blocks were probably intended to be used with plain colored sashing. Yellow or green or blue were favorites or even red - although it was likely to run and was not used as much. Bubblrgum pink was a vegetable dye (annato) and had a tebdency to fade although it was a pretty color.
Jeannie