I use a 12" steel challenge round steel plate as a target to practice my double action revolver fast draw against. I shoot it from a distance of anywhere from 4 to 10 feet. I have used lead, plated and powder coated bullets in .22 LR and 38/357.
I have shot 1000s and 1000s of rounds doing this with no backsplash hitting me other than an occasional dust sized particle. The most important things for safety are to make sure your plate is 1) of proper hardness, 2) not dimpled and 3) properly angled - the top of the plate should be closer to you than the bottom of the plate. This angling of the plate directs bullet fragments into the ground at the bottom and to the left and right of the plate stand.
If your plate becomes dimpled, it was not of proper hardness and must not be used for close work.
So, in my experience, yes, plated bullets and lead bullets both fragment similarly when hitting properly hardened and properly set-up steel challenge plates.