It doesn't surprise me that this question gets asked. I had a cop tell me it was illegal to carry in a bank because it was a "federal building". This is bad information. The bank's federal protection for your savings does not make it a federal facility.
I've carried openly in banks as have many others, so concealed is no issue.
As a side not, you CAN carry concealed or openly *into* a courthouse and by law the courthouse must provide secure storage for your sidearm. I somehow let my CPL expire many years ago when I lived in Tacoma, so I carried openly to the courthouse and checked it in while I visited LESA.