Well I currently own 73-47 that was originally fitted with PF-5 electronics. I also owned 74-49 that was fitted with PF6 electronics. So, if Mr. Johnny Long says it is a 1974 and it show it having PF-5 electronics, it MUST be 74-48.
I guess 74-49 was the first bass with the newer PF-6 circuit.
Michael