Prior to noticing the chassis #, it looked like a 1956 to me , only because there were vertically-oriented chassis used in 1958 and 1959 sets. I have a 21D9475, the fourth digit is the year. (21 inch "deluxe") mine's a KCS121
Yes Dieseljeep, I despise those clips.
I am also picking one up
http://harrisburg.craigslist.org/atq/3265893634.html
(I hope) tomorrow for a similar price, so I'll have two.
Something about the channel window on these.....