That policy is from someone in Miles City, MT. Where did you find it? Is it because they don't like guns or is it because they don't want to be liable for the value of the vehicle's contents?
Google Fu seems to confirm what I thought when I saw Miles City. You can read the business through the Sharpie on this larger version.
http://theconservativetreehouse.files.wordpress.com/2013/01/geico-768x1024.jpg
It's this company that makes chamber adapters. Posting this to gun forums is not a bad way for him to promote his small business. Hmm, very clever.
http://www.gunadapters.com/
The original Facebook page of the policy holder.
http://www.facebook.com/pages/gunadapterscom/124696527577866