@DannyITR1 @mattydexter When you replace any ped files, there are usually duplicate files of the ped in the update dlcpack folders. Within there, you need to go into each folder and make sure that there is not a duplicate file of that ped. If there is, you need to replace it with your files you intend to replace it with.
The game will not use the replaced files until you replace every single dupcliate file of that Ped.
Also Matt, you can actually install that robocop ped as addon to make life easier if you wish.