Hey I can pickup a 20# tank that's stamped 2/10 locally for $100, I'm going to get it this afternoon but wanted to see if I was missing something. Guy says it's full and the pic looks shiny and nice. Is there a chance it's filled with something else? A way to check? Is it kosher to put this thing in the trunk while I do some shopping (have to travel to meet him)? Anyways thanks for any help from a lurker.