As if to confirm the latter hypothesis, we found this gem on the street as we walked home from breakfast this morning. The photo hardly does it justice. The car itself is a brighter yellow with that tinge of green still visible. I am guessing this beamer is from the 1970's (not being an fan), and that this is the original color. Cars used to come in different colors, and not just the ones trying to look quirky like the Fiat and the Scion. We remember purple cars of all shapes and sizes.
A note on that license plate: PULAAAY. Is it an emphatic pronunciation of the imperative: Play! Or is it a pun on the French poulet? Again: retired.