In the runouts he can be identified by 3 or 4 digits, like e.g. 7C1 or 12C1.
The first 1 or 2 digits stand for the week the record was cut (1 to 52);
The C is the first initial of his full christian name;
The 1 means that it is the first cut (2 stands for the second cut respectively, asf.).
The digits can be found on nearly all of his cuts between 1972 and 1990.
K.G. or KG in addition means that he also mastered the release.