I have 6-7 of the BN-2A in my book, from years ago. Oldest was ZK-FWZ from memory. Fantastic 'ol girl to fly ;-) Unfortunately, I never did record her serial number, but if memory serves, was sub-200. Reputed at one time to be the operational Islander with the highest recorded number of cycles on her.
There's bound to be someone who will stumble on this page that could trundle down the tarmac (NZNV) and have a look at that serial ;-)