Should the letter "Q" be included in the marking of 5962-3812802VGA?

I coincidently found two pictures of this part, they showed ADI logo, "5962-XX" part number, data code and serial code. However, there was one difference, the first one had a "Q" letter in the marking, the second one didn't.I know "Q" represents "QML", and I have searched on ADI website, but found no useful information to explain it clearly.

So, could anyone please help me on this, and is there any document about this?