If you look at anything made by Caterpillar
everything has grade 8 bolts,even the dash panel! Of course the dash panel doesn`t need grade 8 bolts but it adds to the air of indestructibility.
We usually upgrade to grade 8 also,just because we can. The latest option is a 17-4 precipitation hardened stainless steel bolt kit. Much stronger than grade 5 and rivaling grade 8 they still resist rust really well,plus they`re pretty.
Nice to know you`ll never have to fight with those rusty bolts
ever again. Mark SC&C