Does anybody know how to identify the Am386 chips manufacturing date correctly?

Here's what I mean, one of my chips reads:
D 9429DPB

And the others:
D 40489JS
D 414WZN7
D 3011HKK

So, with the first one I would assume it's year 94, week 29.
But what about the others? I'm guessing the others are omitting the 9, hence they are 9404, 9414 and 9311.
It seems that they changed the pattern in 1994. Does anybody know why? And what is the meaning of the other numbers and letters?

I have two 132 PQFP to PGA adapters with a soldered Am386 DX-40 and there's one of them that has 4 capacitor-looking SMD ICs. I'm not sure what they are. What are they? Perhaps L1 cache? xD
Notice the other adapter has 8 empty pads.

I'm inclined to think that they included the capacitors to give it some stability perhaps, but I'm shooting in the dark.

What do you guys think?