pak modification

Its still possible to modify the pak file to get the exclusives? because i can extract, but i'am a newbie in .pak modification, so i have no idea how to modify the pak, and i dont want my effort to just discover in the final that you can only get the exclusives through CE. I'am using umodel btw.

This does work but players can't see you and you get kicked from playing 1-2 more games saying about the modification.