iPhone 12 Pro Max Network iPhones still unlocked until first sim is inserted ?

[winrya]

Tried a search but can only find the answer with previous iPhones. Years ago iPhones purchased from uk carriers would lock to the network of the first sim card inserted. Is that still the case now? I’ve been offered a sealed 12 pro max from an ee upgrade. I’m on Vodafone unfortunately but seller believes is unlocked until sim is inserted.

Anyone know the current situation. Seems phones from 3 network are unlocked but not sure about the others?

 

[MarkX]

EE phones are not unlocked until 1st sim is put in.

It is locked to EE from the off and cannot be unlocked within the 1st 6 months of the contract.