Using OpenIV open 
GTAV/update/x64/dlcpacks/patchday3ng/dlc.rpf/x64/models/cdimages/weapons.rpf
drag and drop them into this folder and delete w_pi_sns_pistol+hi.ytd

for skins:using Openiv open GTAV/update/x64/dlcpacks/patchday3ng/dlc.rpf/x64/models/cdimages/weapons.rpf, find w_pi_sns_pistol.ytd,open it and drag frame_00_00_00.dds into them.

enjoy