Overlapping Inline Ships
You would indeed be able to K-Turn both ships, as as you are not touching and no overlap occurs.
While the FAQ specifically mentions two same sized ships executing the same straight maneuver. But it applies equally to other situations. You need to cause an overlap and move the ship back along the maneuver template to be touching.
There is a sound argument that a straight maneuver is different from a K-turn maneuver. Therefore the "Overlapping Inline Ships" rule is incomplete/incompatible. Here's a definite answer though, which satisfies both ends of the argument. If you two ships were touching and parallel, when they k-turn the same speed, there is no physical way for the bases to overlap except for the movement guides which count as part of the base for all purposes except for range measurement. So as long as the nubs don't cause an issue, there's no bump anyways.