I prefer to see my tyres before I buy them. Tyre sizes are so variable that you can't trust the specs.
I replaced some 28mm with the same size from another make. I measured the width in the shop, and they were more like 25mm, so I ordered their 32mm instead. When they arrived, they were still narrower than my old 28mm, but good enough to use. By using an LBS, I didnt have to pay any postage, and the LBS will be there when I really need it.