Jesse, good find. Some line manufacturers actually mark their lines at one end or the other. I have some cortland lazer lines that have very small print telling you they are 333/444 WF/DT and line weight. Strip it out and see if it has it on the end toward the backing, you'll also get to stretch that line out, see if it has any knicks or kinks and if you can compare the line at the two ends to see if it is a DT or WF, not that it probably matters much. If you can find a scale in grains you're set. If not find one that does grams and convert grams to grains : 1 gram = 15.4323584 grains I have done this a lot when I have foolishly failed to label lines and then not known is it the 3 or 4. Let me know when you find out you hate that reel. I have a 3300 and 3200 but have not been able to find a 3100 yet.