Look at his/her feedback first, I personally would be cautious of the person who just joined with no posts or anything, txt or talk in person, use your gut. If it don’t feel right maybe it isn’t.
On the main page at the bottom just below the "Member Classifieds" is " Member feedback" do a search there to get results on a member you are inquiring about.
If they email or pm you with a "buddy who has what you want...just email him..." That is a red flag.
Click on the member who you want to know about. Click on the FORUMS tab to see what topics he has created. Read them, if they are quality posts then click on REPLIES CREATED tab. Read those. Scammers will not take the time to invest in building a profile that has quality content. YMMV.
Do your homework or ask the membership about first hand experience with that guy.