Curiosities about the serial numbers engraved on the dashboards of the Atari light sixer pal

[daryuss]

I recently exhumed my Atari light sixer (pal-ita) purchased in Christmas '82 (one or two days before December 25th) to check its operation, after many years I noticed that under the power supply connector there is engraved this number: 231 (first image)
What did the Atari factory want to point out? Maybe 23rd week of 81 or 31st week of '82?
However, doing research on google, I only found this photo with the serial number engraved on the dashboard of a light sixer: 289 (second image)
It can't never mean 89th week of 82! Perhaps, 1982 August 9?
Except in 1989 they were still reconditioning the light sixers, these that have been out of production for about 8 years!!

 

Another curiosity is: why they put such high serials on the stickers stuck under the light sixer pal, for example mine is: 549.266.031 (units manufactured?)
I await the comments of the great connoisseurs, possibly those who worked in the Atari factory in those years and who are now registered in this forum ...