It all depends on how legitimate the claim is- or appears. If you take it to a long-time, well-known and reputable dealer and they work with you on it, you might get a clean shot on something like bad gas. If the insurer and adjustor know and trust the dealer, I doubt you'd be black-marked. On the other hand, if it looke dquestionable and the insurer pays it simply because they know they're going to pay it eventually anyway, then maybe.
You don't say what engine it is or who's insuring it. If it was a $15k engine, a couple-year rate bump might not be all that bad. And it's rarely "just a piston".