Not only that, but those stamped numbers would had to have had successive coding for versions of the same shifter series. Pete Serio told me of at least 3-4 changes in the 69 model year alone due to all the change orders GM sent to Hurst regarding the column lock and the changes that brought throughout the year. I would bet one of those characters in the stamp is the series for revisions. I'd guess it was the first because of the 1/2/3 but then why the 6 or 8's later in the year? Or are there actually other prefixes such as 4/5/6/7 that we simply haven't seen yet.
Here's one from another 69 that starts with a 3.
So much is still unknown about shifter coding, dates and batch codes or series? It's fantastic to have CRG and its members compiling data such as this, but there's a lot more remaining to be learned before attempting to pull an actual date from this code, or how it can actually be deciphered.