I daven nusach Ashkenaz. I often find myself davening in a nusach Sefard shul. While I consider it nice if there is a NA siddur handy, the bottom line is that, as a guest in the shul, they do not have to have my particular nussach siddur on hand to accommodate me.
In short, if you aren’t going to daven the nusach of the shul, bring your own siddur. Don’t complain that they don’t have your nusach.
The Wolf