I've noticed on my Shelby that the tube, collar and upper hub are just different enough in paint application that I believe they were painted separately. For instance the lower collar has a slightly better finish quality than the upper hub. That is to be expected if they are painted apart.
In my experience that observation is interesting since the vast majority I've seen have much worst paint and condition on the surface exposed to the engine compartment elements as one can see in the upper picture posted above. Plenty of chances of spilling/leaking brake fluid, heat, grease and other things
On the upper portion of the tube there is what appears to be a date in light colored ink stamp. I'll look later to see if I can decode it. I thought at a glance it was a 3 digit day of year?
Guess you referring to the stamped number rather than had written markings some times documented
For 67 steering column main tube I've got month. day of month and year as a single digit all in a string of numbers - no spacing
The method of marking when the steering column changed for 68 and up assembles