All you'd have to do is make the change in your item's Product Notification URL setting; your existing purchase button codes in your site would pick up that change automatically.
These copy-paste and print restrictions depend on the buyer's PDF reader app respecting them -- e.g., Apple's Preview app for the Mac has been known to ignore the copy-paste restriction. If the reader app respects the print restriction, it should not allow printing at all, neither to a physical printer nor to a PDF "virtual printer", since those both use the same Print function in the app/OS. Generally we don't recommend using these restrictions anyway, as they make for an unsatisfactory customer experience if they can't do common things they'd normally expect to be able to do with any file on their computer.
