Does the iPhone 15 SIM tray have the model number?
iphone 15 have model number on sim tray like in this photo
iPhone 15, iOS 26
Newer iPhone models do not have the serial number engraved on the SIM tray.
Find the serial number, EID, or IMEI on your iPhone, iPad, or iPod touch - Apple Support
Also check this discussion about it:
i bought new Iphone 15 and serial number … - Apple Community