left to loosey or right to tighty

[butthead]

hi , can anyone tell me with certainty if the handle bar mirror mount thread on the clutch side of the bike is right to tighten to left to tighten.  i have a mirror stalk in it atm and its been in there a long time through winter and summers, so it will be stiff to undo as a result, but i think one of the mirror stalks is a left hand thread and the other a right, i cant recall which?
  i dont want to strip the thread thinking age has made it very stiff to undo when im actually over tightening it