Regarding the inspection process, who uses a borescope or other tool to do a checkout? I will be buying new (NIB) firearms to at least get a manufacturer's warranty on the item. Has any manufacturer ever refused to honor the warranty because the original dealer was not an authorized seller? How does a buyer know that he is not getting a gray market weapon?
I think it is a shame that dealer inventory is so low in Oahu, and many will not even order direct from the manufacturer due to supply problems.
Go to their websites to read the specific warranty for a firearm.
As for the dealer's status, most warranties i read don't mention it. However, some like Remington will automatically register your firearm so warranty claims can more easily be processed. Glock requires a card be filled out and returned within 30 days of purchase, but will also accept a dated invoice or receipt as proof of purchase date.
Sig Sauer provides a limited lifetime warranty on all firearms to the original purchaser.
Smith & Wesson only provides a 1 year warranty to the original purchaser.
I've seen someone post that KELTEC will transfer the warranty one time (second purchaser), but that's not what my KELTEC KSG manual says -- "original purchaser only". Make sure you verify your specific warranty and don't just take the word of some random stranger on the Internet.
Warranties can and do change, so any information you get secondhand might be out of date.
If warranty coverage is a deal breaker for you, make sure you compare warranty terms between all the brands you are considering.