I think this has been said before but "best" varied from age to age. For example, there are best Purdey hammerguns made well into the 1900s because that's what some very high end shooters wanted.
I would certainly not be surprised to find a London best without ejectors up to 1898 (and, as stated above, beyond but that would be an exception).
If the gun is as originally made (or as close as would be expected given its age and normal maintenance but then with a discount), not one of the lesser grades, and in good shape, I would let it join my other London bests.
Competition was fierce by this time in London. If the gun is the top grade, Purdey made it as a best gun. After all, the shooter likely had a loader for that shell kind of thing.
