A small detail in Thibault’s Académie de l’Espée that had escaped me so far: on Table 27 the rapiers are shown with perforated plates on the front openings:

Using Norman’s typology, Thibault’s prescribed hilt is composed of an outer guard of type 43 (two parallel side-rings) and an inner guard of type 25 (two tangential curved bars forming a cross). The front openings are the most exposed when both fencers use an extended arm and sword position, as became common with the rapier, and these small plates are the first to appear in the 1590s, before the advent of the more developped shells eventually culminating in the Pappenheimer hilts, which by the Académie‘s publication were already starting to appear.

Thibault is quite strongly opposed to newer hilt developments, so much so that I was so far hesitant to assert that he would have accepted the addition of plates or such. Apparently, these at least were possible in his view!