How much muscle m can you gain in a month if you had like basically no muscle from the beginning?

I just started working out running and walking at least 3 miles everyday. Also I have been doing muscle training once a week and some cardio workouts( but that also includes weights, squats, and lunges). I have gained 5lbs in 1 month but idk if all of its muscle weight? But I know some of it is because I actually have some muscle on my arms, thighs, and calfs. I use to have NO muscle! I have also increased my calorie intake too. So do you think this 5lbs could be muscle weight?