The only way you could find out for yourself is to drain the fluid, then fill with the appropriate amount. You factory service manual should tell you what that amount is. If you are the original owner of the bike, and have never added oil, either something is clogged, or that's normal for that bike. It doesn't seem like that's normal though. Personally, I'd remove both legs, empty them out, put a cleaning solution in, move them up and down to wash the ports out, then drain, and fill with new fork fluid. If the bike seemed to soft or too hard, you usually have a couple of different weights oils that are recomended, the heavier oil being more in weight (viscosity).