BF42 accepts every file you tell it to accept
. All the ".inc" and ".con" files are simple text files, and you can tell BF42 to read and process them by adding a "run xxx.con" or "include xxx.con" line to any file that already gets processed. E.g. the vanilla maps only have their init.con that consists of a lot of "run xxx" commands, telling the game to read the other files of the map.
You should definitely make sure to transfer all code that is associated with the weapon. The 1pAnimationsTweaking.con for example is used to fine-tune the speed that 1p animations get played. If you do not transfer the original values, the game will assume you want the animation to be played at 100% speed of the animation .baf file. There's almost no vanilla DICE weapon that uses 100% speed, as you can see if you look in said file. Most get slowed down or sped up so they look correctly.