Nick,
I used stainless steel carriage bolts to secure my bumpers, they weren't polished. Prior to prime and paint I lightly sandblasted them to "rough" them up a bit.
Bruce


Bruce
Old Toy: Ol' Betsy stock 59 Apache SB Stepside (Gone but not Forgotten)
New Toy: 1962 Impala SS Coupe
The Driver: 1990 Toyota truck