[squidtone]

I just ran across this in my 1967 Pontiac Shop manual.
On page 0-4, it discusses the new keys used for 67. It says they use new keyways and increased number of biting depths compared to 66 and older keys.

However, despite being new type keys (keyways), they have an illustration of the key shape, and they are the classic octagon for the ignition, the "A" key, and the "B" key is round for the door, trunk and glove compartment.

It goes on to explain how to determine your key code by looking at your key and comparing it to the positions listed in the manual.