Hong Kong, Government of Hong Kong, $1, Specimen, 1954, green on grey and multicoloured

Hong Kong, Government of Hong Kong, $1, 'Specimen', 1954, green on grey and multicoloured underprint, Queen Elizabeth at right, value in Chinese and Arabic numerals at four corners, perforated 'Specimen' bottom centre, ink annotations at top on top border, (Pick 324Aas), few pink ink spots on obverse, key date of the series!