What you want to avoid in your hub is links to sites that sell guns. It would probably be best not to discuss value of said guns either. Try to attach sentimental reason for each weapon.
Hubpages has strict rules in some aspect, so be sure to contact Hubpages' help pages. There are some issues that Hubpages wishes to stay clear of. The messages you get are simply warnings....like when you start a hub but save it to finish later, the message is a warning of article is substandard. It is just a way to let you know where you are with the article. Guns is probably a touchy subject. Write it anyway and try to publish. See what happens....if they reject it, then study why and rewrite!