...as long as that metal is nowhere near the refueling vapor area...........
  Also, did you know that the nozzle MUST remain grounded to the filler neck of whatever container you're filling during the entire fill-up?  The fuel rushing thru the fuel hose will generate static electricity and can cause a spark when it builds to a level high enough to arc the gap between the filler spout and the filler neck.

Mike B.