I believe it to be from 1948, but without taking it out of the plastic, I cannot verify.
Vintage Magazine Ad General Motors Locomotives Rock Island
Vintage Magazine Ad General Motors Locomotives Cotton Belt
NOS EMD Electro Motive GM General Motors Locomotives GP-30 Ad Insert Proof 1961
NOS EMD Electro Motive General Motors Locomotives GP-35 Rock Island Ad 1965
NOS EMD Electro Motive General Motors Locomotives GP-30 EMD Generic Ad 1962
NOS EMD Electro Motive General Motors Locomotives GP-30 L&N Railroad Ad 1962
