Yes, most Japanese people wear their wedding ring on their left finger. Kazuma noticed the ring he gave her from day 50 is on her left finger here. He was asking if there was any special meaning "here" because he's in a different world. It was entirely possible for her wearing it on her left ring finger to have a different meaning in the Konosuba world, but it just so happens to mean the same thing as our world.
Edit: I think I can see how this page may have needed a bit more clarity, I updated the wording to hopefully make it more clear to future readers.