Wiring diagrams for the 71 and 73 are available here:
http://www.pelicanparts.com/911/911_...l_diagrams.htm
They both show the same type of wiring as is used on most VWs. I believe that the Ghia regulator should work fine. The red, green, and brown wires should be the same as the Ghia (+12V, field, ground), and the blue wire runs the alternator warning light. And is part of the circuit that "jump starts" the charging.
--DD