Not usually. Check you MB specs. Sometimes PCIe slots share bandwidth with other slots. X16 SLI and Crossfire slots share bandwidth with each other. Total bandwidth is x16 and when adding another card the two slots are usually throttled down to X8. I do not think that a x1 slot will throttle down or even can throttle down any.
Yeah, that's kind of what I figured, but I wasn't sure. It would seem kinda odd if it downgraded all the slots/lanes, since the 1x are kinda meant for slower devices that may not be the latest version of PCI-E