I don't think the self-moratorium includes the brake balance system, at least it is not mentioned as such on McLaren's letter, which namely includes:
1. Quick shift
2. Fast fill
3. CO2 as tire gas
Nevertheless, regarding the brake balance system,
"detailed examination of the report shows that one area where McLaren had appeared to utilise the Ferrari information was in the creation of a new brake balance system" (Quote is from autosport, see the link below).
The WMSC transcripts also show that McLaren went back to using such a system (they used it in the nineties, if I remember correctly and had to repackage it), although technically different, after they had some idea about how it works from Coughlan through Stepney. McLaren, on the other hand, claims that they had information on how the system works by other means, such as analyzing onboard videos, photographs and so on.
You can read more about this here:
FIA: McLaren planned to use Ferrari data