He's possibly the only reoccurring black character, and yes it is very much a product of its time.

In defense of the authors the Gauls are all depicted with large bulbous noses, the Romans with Roman noses, etc; all cariceturs. https://en.m.wikipedia.org/wiki/Caricature.

In the attached image you can see Obelix is also depicted as a "knuckle dragger" (at times). The character leading them is a Roman.

This second example shows the Vikings.