On Facebook -JOIN I Antique Online.com: Collectors of Antiques and Collectibles.
Here is the link for the group https://www.facebook.com/groups/327133184409134/
Please join our FB group where YOU can post directly.
A Community For People Who Buy, Sell or Collect Antiques, Collectibles and Art
When the particular dairy is not displayed on the bottle directly, it may mean the bottle is simply a generic milk bottle not assigned to a specific dairy. Therefore, mass-produced and cheaper for the dairy to purchase. The code M 3238-S may simply be the bottle code not a dairy code.
When the milk bottles were made with the particular dairy emblazened on them, it was usually obvious enough which dairy it was that a particular code would not be necessary.