DMK and DBK compared, I mean physically. They're identical essentially.
The looked very much the same from outside, the DBK has a 1.25" nosepiece attached. When I bought mine, they didn't come with 1.25" nosepiece, but AFAIK, it comes as a standard item now.
My DMK is way lighter than my DBK for unknown reason.
Can you tell which is which? The one with bigger imaging area is the DMK, and the one which generates colorful reflection due to the Bayer matrix is the color chip DBK.
From the side, very similar in appearance. Notice that the ring on the imaging port is a CS to C mount adapter, C mount and CS mount are identical except the difference in back focus which can be made up with a simple ring as shown here. They come standard with a DBK/DMK.
Newer model has longer mounting plate, DMK on the left and DBK on the right.
At the back, they're the same, nothing but a 6-pin 1394 port.