Yes they are. When creating comb. novs. Paul Kirk automatically picks up homotypic synonymy in SpeciesFungorum but wouldn't have been aware of the heterotypic synonymy so that entry is currently wrong. I could have used Horak's earlier var. gracilis as the basis of the combination, with a stat. nov., and sunk austropratensis, but Horak's epithet was based on seeing few specimens and the taxon is usually far from 'gracile'. Young's epithet makes more sense and the name in Cuphophyllus is clearly needed. The synonymy is based on multiple sequenced vouchers on both sides of the Tasman. Mine are about to be uploaded to GenBank and I think Tom May has the Australian ones, or Teresea Lebel - I forget the provenance. There are numerous such Australian names that clearly need moving and should be done. This is a cross-Tasman species and I try and keep NZ names current.