Under NSW strata law, a by-law does not become effective until it is registered with the Registrar General. It may well be that the strata manager sent you the standard by-laws because he hadn’t got round to registering the new one. In that case, I would say you had a pretty strong argument that you moved in under the previous by-laws. However, the critical point is when kitty moved in and if the by-law had been registered at that point.
As a general observation, this is exactky why you want a propers strata search done when you by an apartment. A professional will look at AGM and recent EC minutes to identify any changes that may be in the offing that might affect your decision whether or not to buy.
The Owners Corp has a duty only to issue agendas and minutes of meetings. They have no obligation to tell owners when changes agreed have come into effect but a wise owner would assume it was fairly soon after the meeting (although that is not always the case).