That is a fair question! Also, by the letter of the law, if you were buying a BP pistol, to get a permit, you'd need the serial number ahead of time. With a mail-order outfit, I'm not even sure that's possible.
Yes, if you need a permit to acquire, you have to wait for the firearm to be received by your FFL. They in turn send paperwork to HPD. If you try to start the application early, IF HPD lets you without the FFL paperwork, you run the risk of the serial number or some other details being wrong. That will void the application, and you have to start over anyway.
Registration for black powder firearms is not required:
§134-3 Registration, mandatory, exceptions.
:
(d) Registration shall not be required for:
;
(1) Any device that is designed to fire loose black powder or that is a firearm manufactured before 1899;
https://www.capitol.hawaii.gov/hrscurrent/Vol03_Ch0121-0200D/HRS0134/HRS_0134-0003.htmBe cautious that the firearm hasn't been upgraded to allow for black powder cartridges. That voids the exception.
And, if the firearm qualifies as a C&R item (listed by the ATF specifically or is more than 50 years old), you do not need a permit to acquire if you have an FFL-03 collector's license.
I bought a Nagant M1895 revolver on my C&R license. Had it shipped directly to my house. No PTA or FFL/Dealer was required.
I was, however, required to register. They wanted me to have a Long Gun permit, which I did. No pistol permit -- no 2 week wait. Showed them the paperwork and the pistol, left with the registration form.
So, if you do it right, you should be allowed to buy and keep a C&R-qualified black powder firearm with NO PERMIT TO ACQUIRE, and NO REGISTRATION.
That's my view on it. I'm not a lawyer nor an expert in Hawaii law, but this seems like what the law allows.