AFAIK, Naval weapons have no difference between IS & Clan . . . for naval scale, I THINK the Ravens invented some new armor (Ferro-Lam?). Some of those older Hegemony or Star League era ships would have older armor. The Clans would also add lithium batteries to some classes as well. Heck, some have single heat sinks . . .
Some of the one-off ships become a class of upgrades. I think that is the backstory on the Liberators but its been a while since I looked at them closely.
The Du Shi Wang is in Wars of Rieving I think, but I never looked closely to see if it was updated or not. Further, even if there is a RS in that book, unless it has a date associated with the RS (say 3050+?) you have no way of knowing if that is the ship's original configuration, Clan Mongoose version, post Clan type weapon invention Clan Mongoose version, Jaguar mothball version, or Society secret refit. Though if it mounts Clan weapons for the standard then you can rule out CapCon original or Klondike era re-activation.