"If there is no date sticker, the battery will have a strip, engraving, or heat stamp with a decipherable alphanumeric code. Typically found on the battery cover and sometimes on the battery itself, this code can be several characters long, giving the date information in the first two characters in the sequence. The first character will be a number from zero through nine that corresponds to the last digit in the year in which the battery was manufactured. For example, a five would mean 2015. The second character is a letter that refers to the month the battery was made. The letters A through L directly correspond to January through December. For example, the letter 'C' would mean March. Putting it together, "5C" indicates a manufacturing date of March 2015. These characters can be interchangeable, so "5C" and "C5" mean the same thing."
From JDPOWER.com
2014 April if this is the case I don't know what the rest of the stamp means...