The Tech Manual doesn't give the source for the years available paint data. I wonder how reliable the entries are.
I also believe that even if the years may be accurate, some colors were still available for other MB models and a dealer might have made a request for an "other model" color.
I'm usually persuaded about color by the body plate and the Data Card (if available) and a compare to the dash color (which is rarely repainted). In case of serious doubt, there are small hidden areas where the original paint can be uncovered.
When I saw the Tunis Beige Metallic on my current ride, I said, "Hmm, looks like Coffee Ice Cream"...one of my favorite flavors. I took the car home and have enjoyed the delicious (and uncommon) color since then.
If you like the color and the car, I suggest you not fret about color availability. The future buyer of your blue car won't even think about color years and I've never had a judge ask.
Richard M, NYC