If all the mass were to be confined to a smaller radius, it would cause the weight to be higher because the average distance between all the mass and you would be less. If compressed far enough, past the Schwarzschild radius, it would become a black hole. So yes, the weight would increase if the distance was lowered. The mass would stay the same.
Think about mass on the other side of the earth from you, it exerts less gravity on you than the earth below your toes. If you brought all the mass as close to you as possible, your weight would increase. Don't think of the earth as one object, think of it as trillions and trillions of atoms.
If all the mass was at the core and you were somehow suspended where the old radius was it would still be higher. All the gravity would pull down whereas before some pulled at an angle (mass close to surface 1/4 of the way around earth in either way.)