The 1956 proof threepence, distinguishable from the specimen in having a full mirror finish as opposed to the semi-brilliant finish of the specimen strike is the more common of the two strike types. 1007 pieces were struck making it still relatively scarce though many collectors collect the specimen alongside it giving it a total mintage of 1511.
It is interesting to note the differences in the strike depth with some loss of details on the obverse of the specimen strike, particularly on the Queen's hair. It is interesting to note that unlike the 1955, the Melbourne mint was unable to reproduce the details fully on the specimen strikes.