Luckily, that's not the case for the Christianus Sextus, though. I'm using textures for her that the Poseidon models use, and while there's several of them, they're mostly quite small.It does, yes. In that respect, the stock game ships were quite nice. Two textures, one for the ship's hull and one for everything else and that's it.
The new models have LOTS of textures each. And while there's thankfully some re-using of textures, it's still not enough for them to not be a huge hit on modpack size...
That's thanks to some textures being 'repeated', which is done to the model in Maya, which basically means you can make a full-size texture using lots of the same small one.