A scuttle is another name for a porthole. I have seen them molded so they are round seen from the side, my Trumpter “Richelieu”has them for example. But I have never seen them as “deformed” as those on the Dragon Z-39 and they seem to be better on the Trumpeter Z-25.
Looking more closely though, it looks like it is because the hull of the dragon kit has more flare at the bow and if you compare it to photos of the original for example, it is very accurate. I don’t know if Z-25 had a hull identical to Z-39, but if it did then Trumpeter’s model is not as good as Dragon’s by a long way. Everything else on the Dragon kit looks better. In fact credit where it’s due, Dragon’s kit looks dangerously close to perfect.