No, Backes. It's not usual for police to disarm the guy. That's because usually, if they see that he's armed, they draw, and they tell him to drop his weapon. And if he doesn't, they're likely to shoot him. I'm not saying it never comes to grappling with an armed man, but it doesn't usually.
And if it does come to grappling with an armed man or an unarmed man who is just fighting with his fists, the goal is to pacify him. And that isn't accomplished until he is handcuffed. So, even if he does have a weapon, they'll take it away from him, but they won't stop there. They know that the struggle isn't over, and the danger- to themselves and others- isn't over until he is completely controlled and neutralized, and that means getting him in handcuffs. So, they would go right to that, even after he was stripped of his weapon.
You are such a fucking idiot.
In this frame below, the cop in back is covering up the head of "Ruby".
They were all involved with keeping "Ruby" out of sight, so that the people and cameras could not see his face. That's because he wasn't Jack Ruby.