I would have someone who dates quilts by the fabric look at the blocks. They could be feedsacks which are a looser weave. Some look like they could be. I would finish the other blocks the same as the finished ones and make a quilt, 3 blocks by 6 blocks, one left over. Or make another block with reproduction fabric or a feedsack and make it 4 x 5, with sashing strips of the repro or feedsack. You can sometimes find them on ebay, if you can afford them, but at $2 for what you have, that leaves some room to splurge! Be sure to show us your photos!