Help! Not sure which phone I got from amazon! Factory unlocked or ATT or TMO?

[prince_a1]

I purchase a like-new condition Samsung Galaxy S9+ phone from Amazon Warehouse for international travel coming up in couple days. I figured I would have a better chance of getting an authentic phone from Amazon than from ebay sellers. I received the phone yesterday, and here is the situation with the phone:
- The box of the phone says "unlocked by Samsung"
- The sticker on the back of the phone has the model # SM-G965UZBAXAA and IMEI number of a factory unlocked phone
- The actual IMEI of the phone however shows model # SM-G965UZBAATT, which corresponds to the AT&T carrier locked phone
- When I turn on the phone, it shows T-mobile screen and has T-mobile apps on it

How do I determine whether this is a AT&T phone, or a T-mobile phone or something else? Unfortunately, I do not have either TMO or ATT sim cards that I can use to check which network the phone works on. How do I know whether this phone is unlocked and if it is will work internationally? I am not sure how to explain the imei of the phone coming up with ATT model number, yet the phone shows TMO screen.

Please help as I need to get this resolved today, and don't have time to purchase another phone. Thanks much in advance!!

 

[mustang7757]

If you go into settings >about > take a screenshot of the information there .

https://forums.androidcentral.com/showthread.php?t=413366

 

[prince_a1]

The About screen shows the model number as "SM-G965U", shows the serial and imei #, and shows the hardware version as REV1.1