The rust won't (or shouldn't) be an issue, since you are getting em 'new' you can put a good coat of paint on both sides, which is a very good way to prevent rust. And you'd be waiting years for it to show up if you prepped and painted them when you get em. That's far more of a factor than the fact the re-pro panels are thinner. They will bend more easily, so you have to watch if you park it near a milk bar and some tool decides to sit on or lean against the front guards while waiting for their fish n chips (they are thin enough that you can put a dent in them in that situation, they won't crumble to pieces, but they will get a dimple or two potentially) Apparently the main fitment issue of the front guards is the one bolt tab at the top rear near the door hinge. As it's been explained to me (I have a panel of this type but it was already fitted when I got it) you bolt just that one bolt in then pull the panel forward and it bends that tab rearward enough so the whole lot can then be lined up (this will make sense if it's in front of you) and the other thing is the fitment hole points for the front headlight surround /bonnet edge trim piece may need to be drilled as they are solid when you get them. Those trim pieces are available new too (I'll find the ebay link if it can't be easily found)