In general, you'll gain both fat and muscle if you have a caloric excess and you work out. You will lose both fat and muscle if you have a caloric deficiency (more fat than muscle if you eat enough protein and work out). In rare cases you can gain muscle and lose fat at the same time, generally if you start a workout program and are quite unfit to begin with.
Two pounds is within the realm of water weight fluctuations. If you want to know how your body composition is really changing, I suggest a body fat measurement.
My experience as a female-bodied person probably isn't typical for a male-bodied person, but in a year of working out, lifting weights moderately heavy, etc. I have gained about 1-3 lbs. of lean mass. But I think that men doing bulking routines can gain a couple of pounds a month, most of it lean.