I read project readme, checked client side and server side configurations, and no such feature exists - Yes,

The mod readme lists a command to add attributes to a weapon via NBT data, this still uses the pre 1.20.5 Item NBT format, and so any of my own attempts to make this work on 1.21 has failed.

If the mod is updated to use components, datapacks would alone be able to add entire new weapons without changing any vanilla behavior due to components being usable in recipes.

I am aware this feature is partially broken right now anyways due to the bug in multiplayer, but i figured id submit the request anyway, since it has more use now with datapacks.