To the best of my knowledge AWS does not have a code that pertains to copper or it's alloys. Without a code, there can be no prequalified WPSs.
Word of caution, make sure you are welding deoxidized copper, not tough pitch copper.
Al
Even if AWS did have a code applicable to copper, the chances of it having any prequalified WPS's is from slim to none. One must consider the implications of 'Pre-qualified' and how many eras of successful welds are completed in the various joint configurations, welder parameters, materials in use, etc.
He Is In Control, Have a Great Day, Brent