Not usually, no. Most community members actually like seeing an old thread bumped if the new reply adds something concrete. The frustration only kicks in when someone resurrects a two-month-old discussion just to say "same here" or paste a link that doesn't match the original question.
I have done this a few times on product forums. One thread about arcade-style interfaces sat quiet for weeks, then someone added a note about how a recent update changed the daily reset timer. That was useful. Nobody called it rude. What helped is that the person quoted the original poster's problem first, then explained what changed since. That gives late readers context instead of making them scroll back up.
A good rule of thumb: if your advice corrects outdated info or answers a question the original replies missed, go ahead. If you are only adding a mild opinion, consider starting a fresh thread and linking the old one. Some platforms auto-flag necroposting after 60 or 90 days, but that is usually about spam control, not manners.
One exception where it can feel off is when the thread was clearly time-sensitive, like asking whether a specific promotion was still active. Replying two months later about XL live arcade games or slots with daily promotions might confuse people because the offer window has likely closed. In those cases, a new thread with a current date works better.
So no, it is not inherently rude. Just be clear about why you are reviving it. Mention the timestamp gap, add something the old replies missed, and you will probably get a few quiet upvotes rather than complaints.