What is the structure of 2-methylimidazolate?
As far as I understand the IUPAC nomenclature, 2-methylimidazolate would not be the correct name for either structure. 

The term imidazolate refers to the anion of imidazole, though it is not really the correct suffix according to the proposed revision of the IUPAC blue book (P72.1):


  Method (1) leads to preferred IUPAC names. Some names and some
  contracted names are retained as preferred IUPAC names and for use in
  general nomenclature. The following suffixes are used: 
  
  
  ‘ide’ (corresponding to removal of a hydron, H+), 
  ‘uide’ (corresponding to the addition of a hydride, H−), 
  ‘elide’ (corresponding to the addition of an electron) 
  
  
  The endings ‘ate’ and ‘ite’ are used to indicate removal of a proton
  from a −OH group of acids and hydroxy compounds.


The correct term for the imidazole anion would be imidazolide, and not imidazolate as imidazol is neither an acid nor a hydroxy compound. 

In both database entries the IUPAC name mentioned is not imidazolate, this seems to be a trivial name for those structures. So my suspicion would be that both have been called imidazolate at some point, but this does not seem to be the correct IUPAC nomenclature for either of them.