Most likely, it's just a nice legend. The composition of the alloy wasn't much of a secret; the temperature control during manufacturing was far more important - in particular, the cooling process - and it's hardly possible to reconstruct those conditions based on metal chips. With an electron microscope equipped with EDX, it might be possible to determine certain details - e.g., the composition and size of the crystalline phases. Based on those, in principle, some conclusions about the cooling conditions could be drawn, but that's possible now, not in 1946.