EE UNLOADING OXYGEN & ACETYLENE BOTTLES TO REPLACE THOSE ON A PORTABLE WELDING TRAILER. WHEN SLIDING THEM FROM THE BED OF A PU TRUCK TO THE GROUND, EE CAUGHT HIS MIDDLE FINGER OF LT. HAND BETW EEN BOTTOM OF TANK & BUMPER OF PU TRUCK. EE REPORTED INCIDENT BUT DENIED MEDICAL ATTN. ON 10/23/03, EE REPORTED THAT FINGER WAS NOT BETTER. EE WENT TO ER & X-RAY CONFIRMED FRACTURED FINGER.