Well, I havent researched it very much, but 9 cars seems like a lot.
Funny you mention the different colors. With this set I got a extra set of shells, and a special boxcar, the letter says that they messed up the coloring on the shells, and they sent out 2 new shells for the AA's and a boxcar to make up for it. I will take pic of boxcar and the letter tomorrow.
I counted my K-line 027 cars and I have only 7. Must be missing a couple. I'd like to see photo's of that special box car and letter. That in itself if quite a find, congratulations. Some of the rubber diaphragms on the end of the cars were messed up so I have to get replacements. This is one series of cars you can still find new in boxes.
Steve, Lady and Tex