@Jake-Slayer
My guess would be that there is also another texture location for that model in the game somewhere.
Try installing the 's_m_y_cop_01.ytd' here:
\mods\update\x64\dlcpacks\patchday9ng\dlc.rpf\x64\models\cdimages\patchday9ng.rpf\s_m_y_cop_01.ytd
Hint: You can search for files by name in OpenIV by using Ctrl+F3 ('Tools' Tab> 'Search' works also) so if above doesn't work do a Ctrl+F3 search for 's_m_y_cop_01.ytd' & replace the file you find in the highest numbered patchday*ng folder structure.