you could gain a lot of fat..
you could gain some quality lbs.
you could get a little of both.
gear is not a magic pill.. You get out of it what you put into it. Yes genetics can and will play a part.. But if you don't have it (like many of the pro's), then you must work harder than the next guy, watch your diet closely
add and remove things as your body tells you.
very open ended question you have there..