lower and upper control arms had the same type of markings left for left top and botton and the same for right. it should be - for 1 side and | for the other pair. I know that it stopped being done in 67 since they went to a different assembly procedure.
school bus yellow is a part marking =v8. there was yellow, orange and white. I've seen yellow and white but have not seen orange. white was on a 65 dart /6 motor mounts, yellow =v8 motor mounts,most of the paint spots were of varying sizes depending on the parts maker's employee's
you got me on the orange filler plug. I remember seeing them in the dealership but don't remember what it signified