Generally speaking, if the owners corp, as represented by a previous committee has allowed the changes to common property or, more to the point ignored them, then they “own” them.
In extreme terms, in the absence of any paperwork attributing responsibility to the previous and subsequent owners, they could theoretically come into your apartement and reinstate the common property to its original state at their expense. This, by the way, is hypothetical becasue if it went to a Tribunal – which they would need to do – they’d more than likely be strongly encouraged to reach a compromise with you.
Now, you may want to get proper legal advice on this (which this is not) but my instinct would be to go back them offering a compromise, along the lines of you being prepared to agree to a by-law accepting responsibility for the ongoing maintenance of the changes, just to formalise the situation.
However, they would need to carry the costs of the required by-laws since the problem was caused by a historic failure of a previous administration to perform its duties.
It might be worth floating that idea with them informally but if they baulk at the idea, it may be time to call a lawyer.