1203
The placarding for all gas and diesel can be 1203, unless it is a dedicated trailer (hauling only diesel). The placarding on most tankers hauling all products will be the most flamable contents which in most cases will be gasoline-1203.
To the untrained nose I suppose #1 could smell a little like gas. To me it smells like kerosene, which it is. I would not trust the nose. Had a super one time opening old barrels that had lost all markings over the years. He would have me open them and he would take a sniff! I opened an old barrel of additive, he took a whiff and went over onto his back. He came around, but didn't do that again. Turned out to be an old barrel of flow improver, that had weathered down to pure nasty... .