Going a little deeper, then. The etching on B (Boyle) & Gs blades is light. Many, if not a majority+, of etched blades are very faint if not barely perceptible. Particularly if the sword was used. That effect cannot be faked, at least not effectively. Another diagnostic feature is a flaw in the blades just below the ricasso. This is not evident on all B&G swords but when it is, then it is a strong indication of authenticity.
I have one with a flawed blade and near imperceptible etching. After ownership for 20+ years, my friend and mentor,
@TLHS ,examined the etching under magnification and discovered it was Burger Brothers style — a distinctive sunburst. That is a much rarer sword