Matching Numbers???

Hello, cosgig. Was researching some FABO information about matching numbers / casting numbers and found one a response that you had posted on 3/13/10 for the thread "Matching numbers???". (We have a '65 Barracuda, /6, 225 ci) On another thread, I found that casting numbers for this era engines were also stamped just below the 1st spark plug (behind the alternator).
The number stamped on our engine is "A 225 1 18 2" of which I decode to mean a 1965, 225 ci, with a (casting) stamp date of January 18th. But can you tell me what the last "2" indicates?

Thank you so much!