I would bet it's R4 too. R4 is a VERY orangey red. I know my car looks orange in some lights, and red in others.
AMD is the way to go on the metal. They have so much more metal to offer for these cars than you'd think.
I've purchased both fenders, both quarters, both bumper braces, trunk brace, both trunk extensions, outer wheel houses, windshield, battery tray, splash shields, floor pans, trunk pan, rear crossmember brace, rear tail panel. I wish I would've purchased a new hood from them, and they're supposed to be producing a 69 deck lid soon too. Those deck lids are tough to find in good shape!
I purchased most of my metal through "A Deals Auto Parts" in Maryland. They have excellent customer service, and great prices. You buy from them, and everything is shipped directly from AMD in Georgia. It's way cheaper to buy from them than it is to purchase directly from AMD.
Good luck on the project!