It actually was never named or called Apollo 1 pre-fire. The fatal training exercise was later given that designation so that the guys would have an actual "mission" that they died on.
This is another example of how as Americans we're lousy at foreseeing and preventing calamity but good at recovering when it happens (also, see Challenger). The "race" part of the space race (including fears of the Soviets being close to winning the moon race which were later determined to have been unfounded) had allowed safety and quality considerations to be sidelined in a rush to develop Apollo. The shock and ignominy of losing astronauts not in space but in a ground test fire that revealed tragedies waiting to happen forced a reckoning and a deliberatively measured process of major systems redesign that ultimately yielded a much better spacecraft whilst still getting it to the moon within the 60s decade. If there hadn't been the fire, it's entirely likely that the multiply flawed design would have subsequently manifested in mission failure and could have set us back much further in occurring at a later stage of project progression (such as with possibility of, in addition to the CM, an LM then also riddled with similar unaddressed flaws).
As it was, the CM's shortcomings sparked a fatal fire at an early developmental stage that bought the time and most necessarily, the permission, to slow down and find, acknowledge & fix critical issues across the project.
