The "norm" for a yellow mod top on a '69 Plymouth would be Y2 Yellow. F3 Frost Green is also a possibility. The only other color I've ever seen that top with is F5 Lime Light, but that is way darker than what's on your inner fenders.
http://www.mooresmopars.com/modtops.html
so how many mod top cudas were there made.i know of ones thats totally screwed but still in a wrecking yard