I think that's a great price for a quality Colt 6920, I seriously doubt you'll have any regrets.
With the money you saved you could always throw an Aimpoint PRO on there for a few hundred more.
I keep the original paper Trust in my safe and there's also a PDF copy on my home computer and work computer, plus my iPhone and iPad.
I wonder what the chances are that you could request a copy from the ATF at worst-case scenario.
My daughter took up an interest in guns behind my back and when I found out instead of punishing her I took her to the gun range to teach her how to shoot safely.