Agrippa is responsible for reducing the multitude of guards used in medieval fencing down to four numbered guards. While this was quite radical in 1553, by the time we get to the early 1600’s the old system of named guards had all but disappeared. Even Fabris, who depicts a multitude of guards, focuses on the names Prima, Seconda, Terza and Quarta.
Right from the beginning he stresses that all images labeled A are Prima and likewise all images labeled B, C, or D are Seconda, Terza and Quarta respectively. Any differences are a matter of perspective and are not meant to be interpreted as a new guard.
Grauenwolf's Study of Western Martial Arts 