Evidence: Well-supported historical consensus
1948 — Ruess and Vogt
Transmission electron microscopy on dried graphene-oxide (graphite-oxide) suspensions shows very thin, creased carbon films. Thickness is in the nanometre class. This is imaging of the oxide route, not a Hall bar.
1950s
Reduction chemistry, ever-thinner flakes, and arguments about how few layers you are actually looking at. The conversation is colloid and surface carbon, sitting next to growing graphite-moderator and electrode industries.
Why the decade matters
Without this imaging-and-oxide work, Boehm 1962 has no runway. Without Wallace (1947), later device people have no Dirac language. The two threads are still separate.