No. A by-law is not effective or in force until it is registered on title at NSW Land and Property Information (“LPI”). The passing of the by-law allows it to be registered but until registration it has no force or effect (see Section 141 of the Act).
A “gotcha” is that motions passing valid by-laws “expire” after 6 months. If you try and register the by-law more than 6 months since the motion was passed it will be rejected by LPI.
One “solution” is to seek to re-pass the motion at a General Meeting and then register the by-law. Of course the views of the Owners Corporation might have changed so delaying registering by-laws carries significant risks.