If there are any screws/nuts/bolts on it and they are a standard screw head or "slotted" that means it is pre 1950. If the screws/nuts/bolts are not galvanized and rusting this could help you date it.

Back in the day people repurposed their items to make the most use of everything. You are right about the feed sacks. If you removed the the wrap around the frame it maybe have a marking on the fabric giving you a name of what company feed sack it is or what mill and you could research it by the name. The fabric actually looks like flax or hemp. To my knowledge they do not grow those crops in the states. But that fabric could be imported.

The rug punch yarn I cannot tell if it is cotton or synthetic or wool. This would help date it, however the colors in that yarn are after 1915. Dyes in the fibers would be alot more washed out if were earlier than this. If the yarn is synthetic with the colors it screams 50s to me....with the turquoise and pink with a touch of red.