Hey Kiwi.
I have not seen that type of radio before.
Perhaps the NZ cars had a different radio?
They both seem to have a little blue crystal, this usually indicated a transistor model.
Here is a pic of the different types of Air Chief radios offered by Holden.
There was anothers not pictured, one had a dial face that went right to the bottom between the knobs.
The radios in your pic seem to be around the right vintage, late 50's early 60's, and would still look good fitted to an FC. There were many non-GMH radios on the market back then. The knobs on the bottom radio look to be more genuine than those on top. Are there any markings?
Regards
Alex