Do i need a proprietary notice for an image printed in a magazine?

I work in a photo studio and we curently are studying the use off the Unreal engine for some of our production, including 2d printing for third party compagny.
Do they need to incorporate the proprietary notice in ther magazine?
Should it be on all the concerned images or is it ok to only mention it at the end of the magazine?

Also, is this kind of product royalty-free? (it’s a non-interactive linear media so i’m prety it is but just to be sure)

Yes, it’s definitely royalty free and no, you don’t have to put a proprietary notice on use like that.