I don't think it does, it won't break it, but it won't work, or only partially.
I know this because the author used to have a realistic battle pack submod for 1212AD but took it down, so logically this isn't working together. Also realistic archery pack, which is integrated in this, does not work with 1212AD, as he mentioned on the RA-pack workshop.

I am using it till today with mk 1212 and it works at least i happy how my battles are. Maybe not working fully but works..