Calling All AD Sub/Panels: Whats the scoop on Clam vs Barn doors?

[Maximus]

Ive been looking for another project... not that I need one. I really like the AD Burbs and have seen them with Clam doors and barn doors.
What is the value/rarity of each?
when did they make each?

I'd love to see some photos of each?

also... usually the Chevy will usually fetch more than a GMC, but with an old burb how much more/less is a GMC worth?

Thanks!