Rescuing nodeshells can be fun, I've done it myself, but always remember that a nodeshell rescue is no different from any other node in the everything database.
You don't need to add any text to your writeup stating that it was a nodeshell rescue.
As with all nodes you should try to stay on topic, so why mention nodeshells if the title is about THEFEZ's LOVE FOR CAPITALS or so-and-so's conjecture? Another reason not to do this is that Level 3 users (and above) can already see that the author of the writeup and the creator of the nodeshell are different. Being told the same information twice is quite annoying, and may cause the mouse pointer to hover alarmingly over the minus checkbox.

When I see "nodeshell rescue" in a writeup this conveys to me the feeling that the author has a lack of confidence in its quality. It says "well I know this isn't any damn good, but REMEMBER, I was working to someone else's title so you really can't expect too much". Whenever you feel tempted to share with us that you are rescuing a nodeshell ask yourself "If I had thought up the title myself would this node be worth submitting?". If the answer is no, just don't do it.

Finally, nodeshells often have bad titles. They don't really epitomise what you want to say in your writeup. For example, they may be incorrectly spelled or have inappropriate capitalisation. In which case you should simply ignore the nodeshell, create a new node with the title you actually want, and ask a god to dispose of the redundant nodeshell. Whatever you do, don't use the bad nodeshell title and then put an apology at the bottom of your writeup, that's just silly.