Many cartridges are known by different names. Even the factories change the names of their cartridges at times, such as the .280 Remington to 7mm Express back to .280 Remington, or .244 Remington to 6mm Remington.
Or, how about cartridges that have been called TWO different names by the factory at the same time, such as the .30 Winchester Center Fire, and the .30-30 Winchester Center Fire. Winchester advertised both names at the same time.
Or, how about when a cartridge starts out life in one guise, such as a military round, and then becomes a commercial round?
Is it .30 US Government, .30 Krag, or .30-40 Krag?
In the case of the .30-06, is it .30 US Government, Model of 1906, .30-06, .30 Springfield, etc. etc. etc.
The "first is ALWAYS it" doesn't really mean much, to tell you the truth.
It's what people know the cartridge as that is important.
You can likely go into ANY gun store in this country and ask for .45 Colt or .45 Long Colt, and you're going to be handed the same box of ammo.
Same with .30 WCF, or .30-30, .38 Smith & Wesson Special or .38 Special, 9mm Luger, 9x19, or 9mm Parabellum...
You get the idea.