Wow I'm surprised they don't have those "Patented Barrel Rest Standoffs" listed in the Safe accessories section, and no mention on the site how to get more of them..
Have you tried shooting an email to customer service to see what they say ?
Personally I'm thinking of gutting my safe and throwing in one of these Rotary Gun Racks.
It's such a pain to get rifles in and out with the standard safe configurations. you have to unload half the safe to get to a firearm in the rear, if you don't want to bump things against each other, dragging them in and out. . this way I'd just be able to rotate the firearm I want to the front and access it directly.
Best of luck in your search.
"Arms discourage and keep the invader and plunderer in awe, and preserve order in the world as well as property. . . Horrid mischief would ensue were the law-abiding deprived of the use of them."
- Thomas Paine