"Le réservoir d'essence, logé dans la travée principale, a une contenance de 360 litres; c'est un tronc de pyramide à base rectangulaire dont le fond épouse la forme du fuselage.
Fabriqué en duralumin rivé, il est revêtu d'une protection.
...
L'habitacle est équipé d'un appui-tête et bordé d'un bourrelet de protection."
I am french and the bold highlighted part does not normally mean "coated": "revêtu" means covered in a non-bonded way, like clothing covers you. Vêtements, the root of revêtu, means clothing.
It suggests some thickness where the thickness plays a role in the protection, and not bonded like a coat but a completely separate item.
A simple coating like paint would more likely use the word "recouvert" and specify the type of the coating, especially in a technical context. "Recouvert d'une couche epaisse de peinture caoutchouc": Covered in a thick layer of rubberised paint (as an example).
That being said, a very bad approximate usage could still refer to a coat of an unusually thick specialised protective paint. But it seems doubtful, as the term should imply a separable layer that is not chemically bonded, but slipped over.