Here's my model.
Left side, the most noticeable change is the charging handle at the back of the vertical portions of the gun mount. It is simply a hand crank with a pulley on the end. The charging chain from the gun slides in and secures with a T-handle. Charging the gun is done by rotating the handle clockwise.

Rear of the gun and mount. You can see the charging handle better from this angle. The traverse mechanism is more streamlined than the standard Flak 38 to allow clearance for the two equilibrator tubes that extend out underneath. Those tubes extend all the way to the front of the mount. Each has two one-meter long springs in it and are attached to the gun mount via cables. The spring tension counteracts the weight of the gun and balances it for smooth elevation.
Above the traverse mechanism is a piece of sheet steel welded to both sides of the mount.

Right side: The elevation mechanism is completely different from the Flak 38 as well. It's much simpler and I pretty much just cut a piece of thick sheet styrene, laminated it with a thinner piece to get the correct seam on it and cut and sanded to shape. Both traverse and elevation handwheels were grabbed from my Commander Models 90mm M1 AA gun (there were two extras!) and look correct for the late-war spider wheels found on this particular gun.
The sights are correct, however the mounting arm is not. Our sight arm was damaged, so we're in the midst of straightening it, but it is basically a stamped sheet metal arm that is different from any of the options included in the kit. Once we get it straightened, I will post pics. I took the kit sight arm and used the 90-degree angle arm from it, which is correct. It's the support arm that needs to be significantly modified.

Top view: Not much else to say about this

Front view: biggest thing here is the pulleys for the equilibrator tubes. The cable comes out of each tube, comes around the pulley on the front of the mount here and then connects to the angle iron that is the actual gun mount. I have to remove the gun from mine, as the gun mounting system included here (standard Flak 38) is not correct. The gun literally mounts on two 2" wide pieces of angle iron and pins in place.
Also, the front of the gun mount platform has 4 grab handles on it. Cut the two outer (smaller) handles off. That's a Flak 38 feature.

Trailer: The only modification needed for the trailer is the removal of the fenders and the mounting of the toolbox. Two brackets mount it directly to the chassis on the right side. The kit toolbox needs to be filled on the back side (and you can see I haven't quite finished that yet!) and you're good to go.
When we start the restoration of our 1942 Flak 38, I will do a number of side-by-side comparison photos. That'll be later this year!