You might argue that it doesn't matter, and that it has now been invented by common useage, except for the fact that the entire cachet of the cartridge name is based purely on nostalgia; whenever it is mentioned in an American article for example, it's always in a historical sense. And when someone stamps it on a custom rifle it is to hark back to old world British big game sporting rifles.

But if it didn't exist in the past, then there is no nostalgia and there is no history. Then it's just a mistake.

Another example: In the Rigby ledgers the six 7mm sporting rifles that WDM Bell bought from them between 1910 and 1923 are all recorded as ".275 High velocity Mauser". (This to show that even Rigby didn't call the chambering a .275 Rigby - back when they were supposedly making them.)