Yes, get a camera.

Now, Campagnolo made running changes as they felt need be, there were no "model years" per se back then, the Catalogues do assit in dating BUT, the illustrations often were reused even if the part actually evolved. And sometimes the parts appeared or morphed between catalogues. They were about selling new parts back then, not concerned about future vintage geeks.

The screw retained lever arms are earliest, even earlier with no slot at the cable stop and a cast in chromed cable barrel for the cable housing to terminate with. Why change? I bet cost, more parts and much more machining, back then more machining steps translated directly into a higher scrap rate.

When my 1972 Record front mechanism started pulling apart as the upper body pivot bent under load... I asked why, and was advised that before I was born it was better, and had screws...!?! By 1974 the modified design with the extended body that provided an increased pivot foundation and the circlip retainer solved the problem, cheaper and less elegantly.

Finding fasteners for your unit that are correct will be a chore, the tube fastening bolt was different, and the cable fixing bolt had the "washer" machined as part of the bolt, the later separate washer is better functionally as it does not turn against the cable but...you were asking about original.