Shown are 3 varieties, the dropped last "E" of "SPECIMEN" and the small last "E" of "SPECIMEN". There is an Ash variety of the dropped "E" but I do not have that particular stamp in my collection of Coronation stamps at the moment.
A little history relating to the Coronation 10/- SPECIMEN; this overprint was first included in collector's sets about August 1942. The overprint was made on blocks of 20 stamps; two printings were made totaling 16,720 stamps. A number of blocks exist, including at least two forms of 20. These multiples derive from complete sheets sold to the Miller Bros., Melbourne stamp dealers.
This means that 20 stamps of each variety exist in both the Ash and McCracken printings.