We use to decipher the serial numbers of antique slot machines and antique jukeboxes to find production numbers. These were slot machines from the beginning to the end of mechanical models in 1960
(Jennings). Each had a number. I cannot recall if the denomination was the same series or not, but I am sure you are getting the idea. Coin Operated hobbyist magazines would track anything with a serial number. Helped boost subscriptions as well.
The 78 RPM Jukeboxes of the 1930's to the last real collectable ones in 1949 also had serial numbers from #000001 to #0057245 as an example of the Bubble Tube Wurlitzer 1015 made in 1946 with a #10***** and the 1947 #20*****. We got good at it to determine WHICH were low production numbers and when changes took place at specific numbers. Much... like Airstreams.
If there was a Thread where someone wanted, it is a pain in the posterior at the beginning to find the LOW and the HIGH number, the number can be figured out. Some companies will "confuse" these numbers so the competitors are not also up to date with what is being put out at the factory. Each Airstream has a serial number. Maybe they begin for each length, each model, or All combined according to first in and first out of the factory door to a dealer... and so on.
Much like Silver Coins... each year has a mintage. It was fairly accurate until the US Government began melting, say Silver Dollars after WWI, so those numbers are no longer accurate. In many cases off by MILLIONS.
Airstreams should be much easier. Serial numbers on the hot water tank could be a possibility, if they have numbers and only used on Airstreams. Frame numbers versus or matched to the ID Plate on the side of a finished model.
I do not have enough information to find a pattern, but once it is discovered... and Airstream wants to conceal their production numbers... it will get tricky afterwards. Up to now... it should be possible to get the pattern and usually, I say usually, it is easiest for the company to begin with and end with a model year adding a digit with each produced and sold trailer.
Once you have a LOW and a HIGH, you can eliminate any inquiry for those between and begin asking for the NEXT lower or highest number. Getting started was very difficult but easier as the numbers began to fall into place.
As you can tell. Even my short explanation is long... Good luck and with all of the different models out there and sizes... sharpen your pencils!
Among JUKEBOX collectors... having the First of the production and the LAST had a monetary value. For Airstreams... bragging rights.