I've always heard it called a fender tag. The numbers under the ABC123 letters indicates options/equipment the car came with. Those numbers are different from a 65 so someone who had researched 64's might chime in with more info.
Thanks for that, sorry for the slow reply, computer has been in getting 'hotted up'! I notice someone has recently decoded a 1965 tag, I might see if anything on that guys tag is the same. Have a great Christmas.
