As far as length, yes. I looked at pictures of the interior, and the room for the gpus is the same for all slots. There's no partial or removable hdd cage to provide extra room for some but not all of the expansion slots.
However, I just noticed that the max cpu cooler height is listed as "148.5mm / 5.8 inch" (
reference link) and the video card you're considering is also 5.8 inches high, so you might be cutting it close in that dimension, and even if it does fit, that'll exclude the possibility of a side fan.
Also, you need excellent case airflow to handle a single video card that exhausts the hot air into the case rather than out the back, even more so for two of them, and now I'm not so sure the K350 will be good enough in that regard.
On a third note, given that you're getting a Z87 chipset motherboard, you might also be planning to OC the cpu. What cpu cooler were you planning to get? The popular Hyper 212 EVO is 159mm tall, so it won't fit in that case.