Here’s how Sanji’s eyebrows are consistently and normally drawn as shown in both the anime and manga:
Even in Chapter 1065, they’re drawn identically:
And now here are his eyebrows when he’s genes are activated:
Now what do you notice about them now besides the fact that they’re backwards? I’ll give you a hint. The Vinsmokes. Yup, that’s right! His eyebrows are identical to his siblings’ in this state!
But in this specific photo his eyebrows are drawn normal. This is his pre-gene awakening but after gene awakening, his eyebrows are like theirs as shown above. I mean if Sanji in fact was always genetically enhanced then why are his eyebrows normal? Why don’t they match his siblings, the people most genetically similar to him?
The answer should be fairly obvious! Sanji is simply different from them since he still has his emotions. He’s a cross breed between his mother’s medicine and his father’s genetic experimentation. Basically what I’m saying is that Sanji is actually able to remain in his human form then possibly awaken his genetic form at will. The Sanji we saw overpower and bypass the Seraphim’s durability in the latest chapter was his base human state and not his gene activated state.
I hope I explained this well enough and I hope you all could see how I came to this conclusion.
*by Wildfire Kaios