I'd be willing to bet that if you took let's say a dozen random V30's produced in any given year, you'd find just as much variance as the speakers from comparison videos like the one earlier in the thread.
Videos like that imply things like "every 2001 V30 speaker sounds EXACTLY like THIS 2001 V30, while every 2006 V30 sounds EXACTLY like THIS 2006 V30." and that's just not true. Basically you'll find just as many differences between batches of speakers every time a new batches are made.
You can prove this yourself if you have all-like speakers in a 4x12 cab, or even a 2x12 cab. Or even two 1x12 cabs of the same type. Just mic each speaker individually and you'll be shocked how different they all sound from each other.
Maybe there might be very subtle traceable differences over years, but from one speaker to the next, the differences are going to be pronounced enough to make a difference.