Not to be a quibbler, but the sight is the less-common FlaKVisier 20 and not the more-common FlaKVisier 40.

what's the diff between this one and the dragon version really? except maybe a few pieces of PE Juggler

The standard Dragon Sd.Kfz 7/1 has the FlaKVeirling mounted to the vehicle, this one is just the Cargo version with a FlaKVeirling on it's usual base sitting on the back. The CAD drawings may not be reflective of the end version because as they are they seem to just show the gun sitting on the rear deck with no physical attachment. So you get a Cargo version of the Sd.Kfz 7 with some added front armour and a free standing FlaKveirling instead of the seats and ammo storage racks that the Cargo Version normally comes with - though they may well still be in there as unused spares. The fold down sides look to be the ones from the 7/1 as well as the cargo version's sides fold all the way down.

This is what I would call a "transition" variant moving from the Early War 7/1 with the gun attached to the vehicle to the Late War variant with fully-armored cab. They likely just added the vanilla FlaK 38 on its "sled" mounting directly to an Sd.Kfz.7 that had been partly improved (radiator armor, but no armor for the cab as is found on the Sd.Kfz.7/2 kits, and wooden sides). I haven't done a search of period photos to see how common this variant might be.

Deleted due to constant attack by Steve Riley.

Well, I have a fairly good selection of Sd.Kfz.7 photos, both in hard copy and from the Web, and I can say this sled mount is more common on the 7/2 3.7cm version than on the quad 2cm. That being said, I would also caution that photos are just too few to make any generalizations. The vast majority of photos I have seen (and in books) are of the Prime Mover, with the quad and single-barrel 3.7 a distinct minority (not surprising because there were far fewer of them produced). I don't know where CyberHobby got their details. Was it plans, a specific photo, or a post-war version? Without hearing from them, it's difficult to come to conclusions. I also am coming to the conclusion that the Germans made numerous modifications to vehicles without them becoming "official" designations. For all one knows, the radiator armor is a field modification. It certainly looks that way from the straps mounting it to the grill.