I remember reading that she put the gun(s) on the cart and that the assistant(?) director handed the gun to Baldwin from the cart. How much time in-between, if any, I don't know.
Maybe that was the way IT was suppose to happen but perhaps didn't
I think I heard she did that, but wasn't there later when the assistant director got the gun from the cart. I have no idea if anyone checked the gun or the ammo.
There have been a lot of claims of people tampering with the gun or the ammo, but with no control over either, there is no way to prove any of it.