5 digit numbered clubs are special order clubs and consist usually of 2 #'s followed by 3 letters.

I just purchased a used 910F from one of the recommeended used club vendors.  It has a five character serial number due to a shaft upgrade.  The engraving of the numbers and letters is rather sloppy.  Normally, manufacturers take care to assure good engraving.  Is the fact that mine are on the rough side indicative of a counterfeit product?  Does Titleist offer a means for users to query the authenticity of clubs by serial number?