i found the mk2 weapon meta files
i've been searching for about 2 weeks and i found where the other lost weapons and the mk2 meta files
to find the mk2 weapons mainly the assault rife mk2, carbine rifle mk2, smg mk2, combat mg mk2, heavy sniper mk2, go to update/x64/data/dlcpacks/mpgunrunning
to find the other weapon like the special rifle mk2 or the sns pistol mk2 go to update/x64/dlcpacks/mpchristmas2017
and finally to find the last weapons like the cremic pistol go to update/x64/dlcpacks/mpheist3
i hope this post helps you make better modpacks with all the weapons being able to be modded.
@kanadianborn Thanks for the info. By the by, I might suggest you using https://www.gta5-mods.com/tools/car-weapon-folder-for-replacer for replace stuff too. It makes things very very easy to replace Just drop the weapon files inside weapons.rpf and done :3