If you are building the rod and have it, use the rod finish like Sully suggested. It would be the most durable way to go. If you are adding the dots to a rod and do not have access to rod finish, a spot of Sally Hanson's would probably work pretty well. It can get scraped off, though.
You can get a whole rainbow of colors at a ful blown art supply store. Look for the paint markers and get as small a tip as you can. I use gold, silver, white, and a light blue quite a bit. You can also use a fine tipped nib in a calligraphy pen. Inks are available in lots of colors. This is what I write the info on a rod with, then cover with rod finish.