Kiwi. You had better not get in the middle of a Haka. Yes. The shilling looks proof from the picture.
I believe that in 1965, the last year that NZ released these "old" coins, based on the maddeningly-complicated "British" coin-value system (pounds/shillings/florins/pence), NZ made strikes that look "proof like" but also made actual proof versions of these same coins. I believe I have a "prooflike" NZ half-crown and also a "proof" version of the same coin. I will check on this again, but I believe I once read that the "proof like" coins were coins that were made for circulation, but the mint used "proof" planchets. Sort of a "last hurrah," or something like that?
The characteristics that define proof-like coins (mirrored fields and possibly cameo contrast to the devices) are mostly created by the dies, not the planchets.
The edges appear to not be proof edges, but a better focused shot or even an edge on shot would confirm.
There were only 10 proofs made. I STRONGLY doubt that this is one of them - the odds are not in your favor.
I will go with proof-like...its a very nice coin...being that only 10 known proof exists I would have to say that proof-like it is. But you never know...I could be wrong.