Z = factory in China, at that time maybe contracted to Apex

L = year, but I don't know which one because my info stops at G. One could extrapolate further if it were known if letters like "I" or "J" were used.

Apex-made tools were obviously sold at Sears, but also other retailers such as Ace and Summit. Some were even sold at Lowe's as a stop-gap to fill holes in the product lines until SBD could be fully tooled up. But I don't know what date codes would have been then. And Ace has been a consistent Craftsman mechanics tool retailer through the change in ownership, so it's possible that any recent item was available at Ace as well as other retailers.