YEah the 2 on the left are the correct ones, they have a flanged head (built in washer)they must be no longer than them. What he did while not very elegant was functional and no real risk to the plate if he drew them down properly, which he did either knowingly or accidentally.
I think they are "8" hardened bolts. THe one with 2 washers is an 8 looks like. THe phillips is a stretch.