Here are a couple of ways to check if the parts used in your iPhone repair were original or fake:-
1. Check the Parts and Service History (iOS 15.2 and later):-
-Open the Settings app on your iPhone.
-Tap on General and then About.
-Look for a section called Parts and Service History.
If your iPhone has been repaired, it will show either:-
-Genuine Apple Part next to the replaced component (battery, display, camera, etc.). This indicates Apple or an authorized service provider performed the repair using original parts.
-Unknown Part. This means the repair wasn't done by Apple or an authorized service provider, and the part's origin is unknown.
2. Look for Warning Messages (iOS 14.1 and later):-
-In some cases, your iPhone might display a warning message on the lock screen or in the Settings app if a critical component like the camera or display isn't genuine.
-The message might say something like "Unable to verify this iPhone has a genuine Apple [part name]."
More details assistance below.
https://www.youtube.com/watch?v=T5ivmQ53a8w&ab_channel=TheGeekPage