Be prepared to take the sword apart. You will need to remove the handle to see if there is a signature on the tang. If there is you will need to take an in-focus picture of it or take a piece of tracing paper and pencil and create a copy. If there is a serial number on the sword, it's not a samurai.
DO NOT unwrap the handle. DO NOT try to polish or sharpen the sword. Your best bet is to take pictures of the sword and it's furniture first and email those to the appraiser. He/she will tell you if you need to remove the handle and how to do it properly.