dear,
any law firm within jeddah will certify your copies that you choose, i am from al-khobar, so dont have any idea about law firms of jeddah, an attorney is authorized in saudi to verify and stamp your copies as ok, as per my experience, i visited one of the law firm and the attorney just checked my original certificates and put stamp on the photocopies, thats all.
in regards to PCC, the visa office will send you a arabic letter(request letter in arabic to police authority), and you have to take that arabic letter to chamber of commerce for stamp, then you will take it to police station to get PCC.