Just tested with a single page and works really fine!
I’ve searched everywhere and was not able to find a plugin that does just that: activate for specific pages or posts, instead of the whole site.
All other plugins are offering pro versions that do exactly the opposite: activating for the whole site and having options to exclude specific pages or posts.
I really think you should make this an option (activate only for specific pages or posts) as I’m sure many people are looking for this. Just my two cents.
I am exactly in the same situation as this poster:
https://thecartoons.net/2014/03/25/no-right-click-on-single-post/
Unfortunately this doesn’t work anymore without enabling scripts on pages/posts but the situation is exactly as she describes: when you ask for this sort of feature (disabling right click) you get flooded with messages trying to discourage you because you “don’t respect your visitors confort”.
The question here is that the content of MY site is my own property and I do what I want with it and, probably, I have my reasons for doing so… and know quite well that screenshots are very easy to do.