Just guessing here, but surely the only difference between those 2 boards is that the AC4 board comes with AC4.
According to the Asus site (link below), there are 3 BIOS versions for that board, but none of them are specific to the AC4 board.
http://www.asus.com/Motherboards/RAMPAGE_IV_BLACK_EDITION/HelpDesk_Download/Yes, you can use the OC profiles as a template/starting point, and then make any changes from there. But with RAM, you should start with an XMP profile if your RAM supports it. If it doesn't, then yes, change the speed to 1600.
BE WARNED, you'll most likely need very good cooling to run the extreme profile.
Motherboard: RIVE (3602 bios)
CPU: Intel 3930K @4646MHz
OS Drive: 2 X Samsung 840 PRO (Raid 0)
Storage Drive: 2 X 1.5TB WD Caviar Black RAID 0, 2 X 3TB WD Caviar Red, Kingston V100 256GB SSD
Memory: 64GB G.SKILL Ripjaws Z (F3-12800CL10Q2-64GBZL)
GPU: Gigabyte GeForce GTX580 @795MHz - 1536MB GDDR5
PSU: OCZ ZX1250
Cooling: Phantek PH-TC14PE
OS: Windows 7 Ultimate x64. (EUFI)