Are updates from APK Mirror legit the same as Google Play Store?

I recently updated the Google Play Services via APK Mirror and now have the January 1, 2021 version. However, some others told me that the only thing the APK Mirror update does is changing the date (in my case: from December to January), and that Google will later send the same update for the same date, which will be the real update. Anyone else heard anything about this? Are APK Mirror updates legit the same update Google sends, or it simply only changes the date and nothing else? This is for an Android Pixel phone.