Hey Jacob.
Jim’s pieces will need prep work before you can paint. You will need to fill pinholes with Bondo, or UV resin in my case, it will need sanding and then prime , paint and clear coat. The shins will need to be attached in the front and filled and sanded.
Jim’s Kit comes with most of what you need but many have upgraded things like the belt buckle, belt boxes, shoulder straps, buckles.
on Jim’s kit, I have a hard time envisioning attaching them to the chest as they will sit too far forward.