Yes it wasn't until the mid eighties that cars got heavy enough to go to a five on five bolt pattern (which really is not five inches but a metric measurement). Just like the studs didn't increase in size to a half inch, but a metric measurement close to it.
Even though the mid eighties car got smaller dimensionally (about the size of a 1970 Chevelle), they got to be a lot heavier thanks to legislated safety equipment (bigger stronger shock mounted bumpers, side impact steel beams in the doors, and a built in roll over bar in the roof, to name a few).
If you are looking for stock steel wheels try and find them to fit a 1969-'72 Chevelle or a Camaro that was equipped with disc brakes (they are sold new as reproductions) as it will give you a 14 inch wheel in the same size as your old Impala wheel, but able to clear an 11 inch front disc brake. By '73 most factory wheels on most cars had transitioned to 15 inch in diameter.