One Key for a 56?

[Scott R.]

Reading my judging manual for the 56/57, I was surprised to learn that the ignition key (in addition to the doors) fits the trunk and glovebox as well. Was there a reason for this? I had always believed that GM cars of this era had two different key codes, one for the ignition/doors (octagon blank) and one for the trunk/glovebox (pear blank). What year did the Corvette begin to follow this convention?

Since keys are the subject, is there a concise history somewhere of the key blanks relative to the Briggs logo, Briggs logo with R, and those marked with RP (ie, what year each came into use)?

Thanks!

[Gary B.]