I can't speak for ASUS, but I've heard that Gigabyte started releasing their motherboards with the new C2 stepping without a change in model number or revision number.
Personally, I'd wait until mid to late September if you are worried about it. By then most of the C1 boards should have been sold and you have a higher chance of grabbing a C2 board.
Intel i7-4770k, 16GB Crucial Ballistix DDR3-1600, NVIDIA Geforce GTX 660 Ti, GIGABYTE GA-Z87X-UD4H, Seasonic X Gold 650W, Samsung 840 Pro 256GB SSD, WD Caviar Black 750GB x 2, WD Caviar Blue 1TB, Win8 Pro x64, Fractal Design Define R4
AMD FX-8350, 16GB Kingston HyperX DDR3-1866, AMD Radeon HD 6870, GIGABYTE GA-990FXA-UD3, Seasonic X Platinum 650W, Crucial M4 128GB SSD, WD Caviar Blue 1TB, Win7 Pro x64, Antec P280