Transom support plate question

I'm putting an Atlas on my 201 Evo. Looking at the one on there now, there is only a transom support plate on the top bolts. The bottom bolts have a 2" square backing plate on the inside in the bilge on each bolt. My question is whether or not I should buy a 9 7/8" transom support plate for the bottom bolts when I install it? I'm sure it can't hurt but would it still be alright with the small plates that are on there now? There's room for it, I just want to know what is typically used. My boat was rigged at the factory and used by the staff there as a photo op boat before I bought it...so I'm sure it was rigged properly from the start. For what it's worth, it's got a 250 ProXS and the 6" Slidemaster. Thanks.