Strata townhouse - deck maintenance ownership

At the Townhouse I own - owners corporation covers deck. The OC have advised that 1/2 of the deck was extended around 7 years ago and only recently they found out and passed a special by law that that extended part (which was done over 7 years ago by another owner) would be responsibility of the lot owner to maintain.

How do I know whether the deck was part of the original building or not? It looks exactly the same - look / colour / condition wise.

Also, is there a statue of limitation that applies here? They have been doing maintenance on the deck for over 20 years and they only realise its been there - something fishy going on there as far as I can tell.

Thanks

 

Ask to see the original plans to justify their decision.