Columbia actually provided a lot of clues with their habit of including a row of shields on much of their literature.
This page attempts to place some organization on the data I have accumulated. This first shield row is probably one of the oldest made.
From left to right the shields show the C-5.5, the original Sparkman and Stephens C-29, the Defender 29, the C-26, the C-24, and the Challenger 24. Then shown are the C-40 and C-33 Columbia Flagships.
But the real surprise is at the far right: the Columbia 30, 35, and 40 Power Yachts!
How long did they last? How many were made? It's hard to say. It's hard to read the notation in the margin of this photocopy, but it looks like Nov. 1962. The information that I have gathered shows the Contender - not shown in this listing - starting production in 1963, so the'62 date is probably accurate.