In case you still didn't get it after all these years and for all the future danbooru users who didn't get the joke. Captain obvious: Purinz eugen's seiyuu is the same as the one playing Chiyo in gekkan shoujo. Chiyo is commonly lumped together with Paras because of her ribbon and her hair colour thereby making Chiyo=Paras and since Chiyo has similar personality and air around her as Eugen does, this makes chiyo=paras=purinz eugen. Since purinz eugen is an awesome shipgirl, it follows that the paras must have an upgrade commensurate with her awesomeness, thereby the cute ass naval guns on Paras/Chiyo/Purinz. And, I am pretty sure, even if I have yet the luck to recruit Purinz into my naval base, that her guns aren't patterned the same way as Chiyo's ribbon so this is definitely another reference to her.