So this is definitely so cool and it is hard to figure out dates. Even some of us modern quilters like to play with dying fabrics with natural materials.
Do you have any idea of what the inner layer/the batting is?
For me this has the feel of a more modern project, not that older fabrics or even blocks couldn't have been used. I'm thinking there is a connection between the circular design and the Dunlop -- look at the company logo and your letters. Dunlop has been around long enough that feedsacks were around at the same time.
https://en.wikipedia.org/wiki/Dunlop_%28brands%29