Hide a custom post type from Google

Hi,

I was wondering what your suggestion is to hide certain custom post types from Google. I noticed in the header after I create a custom post type there is the following code:

<meta name=”robots” content=”index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1″ />

I would like to change this code for posts with a certain custom post type.

I have tried ‘public’ => false

in the register post type function $args variable however this hides posts completely unless the person is logged in (I would assume) – I want the posts to be visible if someone types in the URL – just hidden from Google.

Any input much appreciated.

Thanks

Best,
Kosta