Yes it does.
After Facebook acquired this photo-sharing social media platform in 2014 it was just a matter of time before their dev team starts rewriting the app.
And when they developed React Native in 2015 it was pretty obvious which framework will they choose.
In early 2016 Instagram team started exploring the possibilities of implementing React Native into existing native apps.
They started slowly with the simplest view: Push Notification. Due to satisfying results, they moved further and started working on other parts of the app.
React Native allowed Instagram dev team to ship features faster to both iOS and Android version of the app. The percentage of shared code is extremely high: from 85% in Comment Moderation view to 99% (!) in Post Promote view.