Are they interested in post cards and books from turn of the century,1880's-1930

I'm pretty sure they'd let you sell them there. It's more of a consignment shop,. Although they do buy things once in a while.

I have seen postcards from across the century.

I have seen some books there. I also think you'll need to go and talk to them in person or call.

Not sure. You would have to call or go in to see.