Other than that odd sqare headlamp (that all the Swiss bikes seem to have), I can find nothing wrong by studying the photos. The PO took pains to prevent paint being worn off the tank by adding those black areas near the saddle. That's the point where my boots wear on the tank so the bike was shown a bit of extra love.
You can change the front fairing and lamps by getting parts in Germany so it looks like a proper AT.
As with any fork conversion, you will want to make certain that the fork travel was built correctly so the front wheel does not contact the frame or top triple-clamp on full compression. Only fiddling with the bike or trusting the word of the owner/builder can tell you this.
Is the rear suspension altered to compensate for the front? Difficult to tell from the photos.
Crashbars are an important addition since the RD03 bodywork is starting to be difficult to find.