Are you talking about "kerning" the f into the fi and ffi?
Actually, I'm talking about the shape of the character in cases where it isn't kerned. Looking through some moderately-old books (before 1970) it appears that the letter "f" only has its "modern" shape when it's part of a ligature. Otherwise the top is much narrower than is common in modern typefaces, probably because of the difficulty in producing overhangs.
Note, btw, that technologies certainly existed in 1972 which could produce overhangs. Someone using a pantograph engraver, for example, would have had no trouble (see an 1878 page of sheet music for an example). Even lead type could reproduce overhanging characters, although the type necessary for doing so was very delicate and would have been incompatible with automated typesetting equipment; it's doubtful anyone in 1972 would use such type for anything except the most demanding documents.
In a way, btw, I find it interesting that while there was no technological hurdle to the IBM Executive producing a lowercase "f" that would overhang the following character (it would probably be possible to modify one to do so by adjusting whatever gizmo controls spacing), it doesn't do so. I'd think the output would look better if it did. I also find it surprising that IBM didn't produce a golfball-compatible version of the Executive (i.e. a typewriter that used interchangeable balls but allowed the crude proportional spacing of the typebar-based Executive). Mechanically it wouldn't seem all that hard.