set, hair costume, make-up, pose etc are more important than lighting

I agree, with the one caveat that the multiple shadows just about have to be there for it to look "right". Umbrellas and, later, softboxes, came into use to eliminate such shadows, and I still have a set of the Smith-Victor aluminum reflectors that were almost standard equipment for work like this. The movie industry and higher-end studios had better equipment even in the '70s, of course, but this is a fairly simplistic stock photo characteristic of the low end of the range for its time.

The black "Loans" nameplate looks slightly out of place to me. By the time touch-tone 'phones in beige were common, white-on-black engraving had largely given way to white-on-faux walnut, and the original wooden holders had been replaced by extruded aluminum holders like the one in the picture.

My last quibble is that the desk blotter was originally an adjunct to the use of fountain pens; the subject in the picture was provided with a ballpoint (the eight-inch long one with no pocket clip, to ensure that it didn't get carried off...) which would have been difficult to use on a soft blotter. Presumably the photographer didn't the sheet of glass that became standard before wooden desktops gave way to plastic laminate.

So, all in all, what you have is an authentic 1970s stock photograph of a slightly non-authentic scene. That should make it at least a little easier to emulate...