I just received my Bostitch MIIIFS and it also came with the extra wide base plate with rollers that can be attached to the staper. I am installing pre-finished 3/4" Maple T&G, would it be useful to use this base plate or just use the stapler as is? What is the experience from those of you who have tried or maybe use this base plate?

I have not tried it. It is supposed to work well from what I have read.

I don't have that gun, but from talk on the forums, isn't that the shoe that your suppose to use for prefinished, to keep from damage, as no sand & finish to cover little scratches and dings.

Yes from what I gather, this shoe / plate is meant for pre-finished floors. This will be the one I use with my floors, just wondering how others found with using it.