Aaah, bullet lube. Lots of discussion about bullet lube.
Is that enough or should more lube be added?
There's not enough information in your question to give a good answer. The short course on lead bullets is that they will leave lead deposits in a barrel, based on a couple of things. If the bullet isn't sized properly for the bore, you'll get lead. If the bullet is the wrong strength for the pressure of the cartridge, you'll get lead. If the bullet runs out of lube before it gets to the end of the barrel, you'll get lead. If the bullet is driven too fast, you'll get lead.
There are also several ways to apply lubricant to a bullet, based on individual preference. You can dip, tumble, or apply it by machine. You can even apply it with your fingers. Some lubes do better at low velocities, some lubes do better at high velocities.
Generally speaking, for pistol bullets, any lube will do. I shoot swaged bullets for target work and they're generally coated in mica or graphite, both dry lubes. These bullets aren't driven hard and the barrel is short, so the lube works fine. On rifle bullets where I'm going to crank up the velocity, I use other lubes depending on what I'm trying to accomplish.
My favorite lube at the moment is Lee's Liquid Alox. I put on a thin coat for slow bullets and two coats for rifle bullets. It works fine for every application I've tried. I don't drive my cast bullets over 2000 fps, but guys that do drive bullets that fast have their own lube preferences.
There is a whole lot more to your question than you might realize, but generally the lube that comes applied to factory bullets is sufficient for the intended application.
