Actually, no. They would definitely NOT have wanted to use the old ones from pre-Dec 1963. So, they either would print up ‘Republic’ ones early, or print interim ones that said something different, which would have added cost by making them print completely different documents to use during the 10 months in question. That would most certainly add cost to do. The cheapest way to go is to print documents that you know you can keep using after the transition that they all knew was coming anyway.
Why would they wait till the official date to get all of the forms...?