Enabling post privacy gating in the Page's privacy settings allows creating of posts with separate Gating and Targeting. Enable:

Post:

Now I have been able to get news feed targeting to work through the api by specifying the param feed_targeting when as specified in the docs.

However there is only one mention of Gating in the docs:

Gating vs. Targeting

Gating a post is restricted to only language and country currently. This is different from news feed targeting because a gated post to a language or country will not show up to a user outside of the gating criteria. Using targeting, the post will be visible on the Page and only visible to those in the targeting segment of the Page. If a user shares a post, the user’s friends will be able to see the post even if they are outside the targeting set.

Is is possible to set Gating through the API?

IT IS POSSIBLE!

1. Make sure that gating is turned on for the page

2. Make sure that you use the page token not the user token.

3. Then when you create you're post with the api the targeting param will perform gating while the feed_targeting param will do news feed targeting.

Note: Gating only works for language and country.