I'll bet those are good places to buy blocks. I think some people die and their things get taken to Good Will or to the Veteran's Thrift stores. One lady passed on and she had a ton of stuff with pieces are packed up in baggies. Her son took it to a meeting she was going to every month at Joann Fabrics and they shared the pieces. He came back again with more that he found in the baggies in an old freezer. Strange way to keep them but I guess is't what ever works.
You got a great find.
Connie