It's really not that hard..
Just search, change text, log out and then choose weapon.

MINI TUT FOR DUMMIES:
1.Search text value (K2 for assault class is DC02) So type in DC02 in your cheat engine after you attach process.
2.Double click the green address(es) in the search result box(Static addresses, I believe).
3.The addresses should be moved to your cheat table, so change the value of the address(es) to whatever weapon you want. Ex: Change DC02(K2) to DC04(FA-Mas)
4.Log out, but don't exit the warrock program.
5.Log back in.
6.Go to the item shop.
7.Choose the service branch(Example I chose was Assault)
8.Click the weapon you changed (K2)
9. Boom. You can now equip a weapon other than standards.