Ipad without a box

Hello. I bought ipad pro three month ago. It was broken some time ago. I was carry it at the autorised service center at 10,Nikolskaya st., Moscow. They sent me letter, that they will give me a new device. I have some qestion about this exchange.

New device will give me without box. Is it normal practical?

How can I recognize that device is new?

Serial number at the my box and at the new device will not match. If this devise will broken too, how will can i carry it at a service center?

If I will want sell device after some time, will i have some document that it new official device?

Regards.