The problem is: (A-K) X 100 = 1100 instruments, not 1000?
I am not sure where the 1000 # came from but I would imagine that QC pushed some to 2nds and some got culled, like in any production process...this could really be qualified as a "Limited Production" in some ways because they were produced at the Custom Shop with a hybrid serialization.
I took possession of K-047 in July 1982, so I would assume your K-043 would have been around that time also. Definitely among the first ones ever made.
My thoughts are they they made all the necks at one time and they stamped them sequentially, beginning with A. Being you bought yours in the middle of the year, I would assume that assembly was done randomly. So Bill, you probably got one of the last necks made, but your CE made it out of the factory in the middle of production. I remember someone on the board owning A002, I believe, at one time.
It is lame that Gibson didn't deal with this as part of its construction process
Norm, I will look at mine when I get home, but I think this was incorporated into the guitar at some point. I honestly think mine has foil in the compartment. I think Gibson made several changes to the model throughout its run in several areas...