In some datasheet (two example in links below) I see only this information, about production date, in marking code explanation:
Date code (A : 1997.1)
If there was a further value I could think per induction but only with this information I can't figure out how to interpret the letters.
My capacitor (Matsuo type 553) have the second row:
63VM. The "63V" means rating 63V but the M what date mean? Maybe it is one date among 1998.1, 2000.3, 2002.5, 2004.7, 2006.9, 2008.11, 2011.1, 2013.3 and so on?
Or there is another way to count?
This is what say the datasheet:
(from: NCC-Matsuo metallized pet film capacitor - My capacitor)
And there it's another example:
(from: Jaro Components Tantalum Cap)