The Lionel cars are representative of 1860's passenger car construction, the MTH cars of 1900's construction. Carbuilding changed over those 40 years.
As far as the MTH Overton cars are concerned, they are based on the former Model Die Casting's HO Overtons, except with a flat roof instead of a clerestory roof. An the MDC HO cars were based on Sierra Railroad's Angel's Branch coach & combine, built in 1902.
Rusty