58 & 59 chevy and gmc trucks are far superior and had all the bugs worked out of the inferior 55-57 trucks
chevy and gmc changed the door hinge bolts in 58, same doors 55-59
they probably stripped a few of the coarse thread bolts in production and changed to fine thread bolts.
don't know about the trim screws though, they only sell one size for 55-59 trucks