On Club Car Golf Carts prior to 1981, you can find the serial number by raising the seat and locating the aluminum, I-beam frame section closest to the batteries on the drivers side of the car. If the serial number plate has been removed, you can confirm it is a 1975-1980 model if it has two brake pedals and one accelerator pedal.
The serial number on your Club Car can help you determine the model year. The serial number of each vehicle is printed on a bar code decal mounted either below the passenger side cup holder or above the accelerator or brake pedal (Example: PH0901-123456, as shown, or F9901123456). The letters or letter at the beginning of the serial number (1) indicate the vehicle model, could be one or two letters. The following four digits (2) indicate the model year and production week during which the vehicle was built. The six digits following the hyphen (3) represent the unique sequential number assigned to each vehicle built within a given model year.
For more information, please visit Club Car Official site.