Earliest and Latest use of "9" at end of casing code / model

[dapellegrini]

I'm curious if any of you can provide an earlier or later casing code example - using the last digit of "9".  Needs to be from the 60's, and needs to have a model / casing code in format ####-####

The earliest I have found in my set so far is the 21-jewel 4006-7019, in June 1967



The latest so far is a 6117-6409 from June of 1972:

[dapellegrini]

AND, the earliest "9" serial that I have found was a Radium lume version...  good reason to differentiate!

[dapellegrini]

The latest -9 watches seem to be "Base Metal" instead of "SGP".  It seems the reasoning fro -9 serials was perhaps first radium lume.  Then "Water Resist[ant]" vs "Water Proof", then finally "Base Metal" vs "SGP"