Does the Best Buy iPhone work in Europe?

[MareLuce]

When I picked up my unlocked iPhone X yesterday at Best Buy, the mobile advisor said that model does not work in Europe.

I said I understand it supports CDMA / Verizon, but I also thought it supported GSM since I wanted to use it with ATT for at least 1 year.

He said it does support GSM and ATT here (in the US) , but it does not support the GSM bands in Europe.
Is that true?

From back of my iPhone box:

 

[dave006]

It will work in Europe on GSM. It will be the SIM Free version if the iPhone X when it is available. The BestBuy rep is clueless as is often the case.

It has the same LET Bands as the AT&T iPhone Model 1901.

Link: https://www.apple.com/iphone/LTE/#iphone-X

Dave