None of the NAMC’s “Catalog of all Series Matchbox Models” (second edition), the AIM's “1-75 Series Regular Wheels” catalogue (second printing, 1983), Stannard, Houghton, or Leake ("Concise Catalogue of 75 Series Matchbox Toys by Lesney" (4th edition, reprinted 2006)) lists any variation not already catalogued by Nick. However, NAMC points out that c/a models have light GPW, whereas r/a models have dark GPW.
U.K. Matchbox did not examine the model.