1968 Build Sheet Wheel Code 300

[OldChargerGuy]

Greetings, B-Buddies.
I will soon be ordering a steel wheel for my 1968 Charger's spare tire. The trunk was barren when I bought it. The build sheet shows the wheel code "300", which should be the Magnum500 style. The tire code is "31", which I understand was an E78-14 bias ply blackwall tire. The car is wearing the original 14-inch Magnum500 wheels.
With this information, can you tell me the details of the steel spare wheel that was originally installed in this car? Wheel width and offset are my first concerns.

Thank you, B-Buds and Babes

 

[The Rebel]

Very interesting. My BS shows 16B for the wheel and l can't remember where l got my info but it stood for 14x5.25 stamped HD wheels.