Legal URI Templates

Just checking, I believe that the following are all legal URI Templates
according to the latest revision:

  {2}
  {%20}
  {☄}

Which does lead to the question of whether
the following are equivalent templates:

  {a}
  {%61}

Previous drafts used

    varname = (ALPHA / DIGIT)*(ALPHA / DIGIT / "." / "_" / "-" )

which avoided this ambiguity.

   Thanks,
   -joe