Get date of last push on github pull request

From the GitHub API you can get a list of commits on a PR, with their commit dates. Like this:https://developer.github.com/v3/pulls/#list-commits-on-a-pull-request

These dates seem to be commit datetimes to me. I was wondering if it is possible to obtain the push datetimes.

I want to recreate the order of comments and commits as it is presented on a GitHub PR webpage.