Although you should keep acetylene bottles upright usually no damage is done laying them down. The problem arises if you draw off acetylene while the cylinder is lying down or shortly after standing it upright. This causes the asetone to be drawn off with the gas making the remaining contents unstable.
So Bob stand your cylinder up and don't draw off any gas for a fiew hours to give the asetone time to resettle.
While we are talking safety never let any oxygen fittings become contaminated with oil, our teck teacher had a large poster in the welding room reading " oil + oxygen under pressure = BANG.