Kamaka does not sell at the factory. Not even if you flash Uncle Fred your best smile and even beg a little - believe me, I tried
You can place an order, but it will take at least a month or so and they'll ship it to you.
My last trip to Hawaii was intended to be a uke buying trip, and I actually came back empty-handed, but that was because I had only one specific uke in mind: a Kamaka pineapple. And I couldn't find one anywhere! Overall I was pretty disappointed by most of the uke shops I encountered - while I wasn't expecting any great deals, I was expecting to encounter something amazing that I'd never heard of before (e.g. a local luthier), or something fairly rare (a Kamaka long-neck pineapple or Ohta-San, for instance) but to my great disappointment, these were only available by the same special-ordering that I'd use from the mainland. Turned out the uke selection was better right here in Santa Monica, five minutes from my house, at McCabe's (which is where I ended up buying my long-coveted pineapple).
My main regret about that trip was that I didn't make it to HMS - can't remember why, but the day I had access to a car and went to North Shore they were closed.