Back then there was a recall on the accelerator pump cup and I think the replacement green or orange IIRC. Found this online.
Chrysler Motors Corp.

NHTSA ID No.: 77V-242

Date of Company Notification: 12-23-77

Make: Plymouth

Model: Valiant, Volare

Make: Dodge

Model: Aspen, Dart

Model Year: 1975, 1976, 1977

Number of Vehicles: 1,300,000

Carburetor accelerator pump seal distortion caused by contact with certain type gasoline may result in persistent hesitation or stalling. Also, premature actuation of exhaust gas recirculation (EGR) system may result in persistent cold engine hesitation or stalling. (Correct by replacing pump seal and EGR system retrofit modification.)