Hi Vic- welcome to the Alembic Forum.
The first two numbers of the serial number will be the year it was produced- so as you have it, the instrument was built in 2006. The 3rd character should be a letter. That letter will tell you what model you have. So rather than a '4' there, what you have is a letter.
If the numbers/letter are hard to read, I'm guessing it might be that the '06 you're reading is '86 and that you're dealing with a 25 year old engraving on the truss rod cover... that would make it harder to read.
If you can post or drop a link to a couple pictures of the instruments, we could probably help out here while you wait for the official look-up from Mica.
Toby