The keyboard can be either the original black model with graphic symbols on the front of the keys or the cream colored Commodore model type with the symbols on top of the keys. It seems that Commodore was just trying to use up all the parts they had in stock, resulting in all sorts of weird color combinations. The motherboard was small and simplified, very similar to the motherboard in the Commodore 64 Aldi version, although some C64G are reported with more older classic C64 motherboards in them...
The SID chip used here is a MOS 8580 version, resulting in sampled sound played at a very low volume. The reason comes from a bug in the older 6581 SID that was removed in the 8580. Finally a fix was found by grounding one leg of the 8580 through a resistor.
Some of these machines were made from Commodore 64GS game console parts when the console was bombed. Most were sold with a game pack (some magazine ads show the same game module as the GS) and were marketed almost as a pure game console that happened to have a computer in the same pack. The G model replaced the awful GS.
The build quality is not very good, especially the case feels quite brittle. The model sticker reads "Made in W. Germany", but the motherboards were probably made in Hong Kong at the same factory as the Commodore model machines and only the final assembly was made in Germany. The machine was probably only aimed at the European market.
The G model was clearly the last cheap game console that Commodore made to get rid of the huge stockpiles of Commodore 64 spares and GS parts. It was also sometimes called Commodore 64-III or C64 BN/E.