The headstock face probably needs a couple more coats of clear at least if it's just got three coats on. As you want it glossy, you should be looking to sand it back flat and then go up through the grits and then polish it as with the body. However if you think it looks smooth enough to you, then you can leave it as it is if you want to. It's your bass!

But you'd normally apply enough coats of clear so you can sand it back flat and not have any bumps from the decals showing. You'll probably see decal bumps on some guitars from Fender and the like, as extra coats and sanding flat all take time and extra cost, but higher-end guitars will tend to have nice flat headstock surfaces. It's purely visual and up to you.