Re insurance. I got an education fro Larry DelGreggo. He's basically the top Parker gunsmith in the country. With Parker values running from $3000 to $50,000, he's often shipping very valuable stuff.
He's also often shipping guns that may have originally sold for only a couple of hundred bucks back when new. He told me of a horror story of a customer shipping an 80 year old parker and it was lost by UPS. They paid him promptly. . . . . the $180 it originally sold for. Not the $4000 it is worth today. I learned this after shipping him a Parker 20 GA DHE, insured for $4000 via UPS for a friend.
I screwed up big time. It got to him, thankfully. But I massively misjudged the value of the gun. (Its condition with intact color case hardening, 20ga , D grade, Ejector all combined to make for a $15,000 gun)
Larry will only ship USPS First Class Registered mail, insured to its current value. The gun is tracked and must be signed in and out by every person who gives it up or receives it. It actually takes a bit longer than regular first class or Priority mail. But its chain of custody is ensured along the entire trip. This is also how jewelers ship expensive jewelry.
Obviously this is overkill for a $500 Glock. But if you ever need to ship a firearm that is really valuable, this is how to do it.