The EC can allow the use of common property as it sees fit but can’t apportion exclusive use to any individuals. Only the owners Corp can ‘dispose’ of common property in this way and it has to be done via exclusive use by-laws passed at a general meeting.
The smart thing for you EC to do is either get a proper legal survey done and apportion the spaces via a by-law, or pay for the creation of storage spaces and let them to the owners for a fee which would go back into the admin funds.
That way people who didn’t want spaces wouldn’t be paying for them and those who wanted more space would pay accordingly. Since owners effectively benefit from the money in the admin fund, there’s no loss of value to anyone.
What it can’t be is a land-grab based on a few ancient stencilled numbers that no one has observed until now.