I saw the cool ones on a CX50 at the dealership and just assumed those would be the ones for my CX30, so I too was a little surprised by the bulkier crossbars when I removed them from the packaging after returning from the dealership, but they'll work, and they are easy to install and remove, so I don't have to have them on permanently, creating wind noise, drag, or the creeping paranoia that something is coming loose.
As for the fact the rail bars have no markings or guide pins, that is definitely not horse and rider, nope. I took a sharpie and made tiny little dot marks at my attachment points after measuring (twice). I also practiced installing and removing them a few times (with a timer) like I would disassembling and reassembling a firearm to learn best practices and efficient order of operations.
I will say this: the non-permanent nature of the bars is not a total deal breaker for me. I installed OEM crossbars on both my FXs, removing the bars prior to selling the first one. Those took a LOT longer to install and uninstall. When my wife totaled the second FX, I went to the wrecking yard to remove those bars in the hope they would fit on my daughter's Rogue (Nissan to Nissan) but nope, no dice. While uninstalling them, the bolts and washers had really degraded due to weathering.
Like an idiot, I put after market cheapies on my daughter's Rogue, and those kind of suck - that's why I wanted to strip the old bars off the FX; they are much sturdier.
Lesson: Go with OEM.