IDK. I went to Apple a few months back to get a new battery for a 6 Plus I bought off eBay. They let me make the online appointment knowing I had a 6 Plus, this after demanding I make the appointment because they would not allow Best Buy to replace the battery (I went there first).
When I got there, everything was ok until I disagreed with the Apple Genius's assessment of my device. He claimed my logic board was faulty because it was shutting down after the battery dropping a large precent. I claimed it was a bad battery because shutting down didn't happen on charger.
He ran a few cursory diagnostics and about 30 seconds after starting says to me "Apple won't let me order a new battery."
Yet, the online appointment system allowed service appointments for exactly that. It allowed service appointments for iPhones as far back as the iPhone 5. But because I disagreed with the genius - no battery for you!
Dude wasn't going to get a sale of a new phone off me - my primary phone an 11 Pro Max was in my back pocket. I didn't/don't need a new phone. So, no sale? No battery.
They could have. They could have even replaced my phone. I got a new iPhone 5 in 2017 to replace my old one. They just didn't want to.
I took the 6 Plus to uBreakiFix which is an Apple Certified Repair store owned by Asurion and got a new OEM battery for it with a one year warranty. Doing just fine. Logicboard my ass.