Radio exchange

Hi all I'm new to this forum business so be gentle. I currently have a 09 freelander 2 that needs a new radio. Now I want to exchange it like for like and there are a few on the internet (eBay ect ...) but I've been advised to get one with the same model and serial number. Now can anyone tell me why this is because the units are identical apart from different numbers. Please help.

You can have whatever radio you want.

You won't get matching serial numbers as they are individual to each unit

Ensure the part numbers match and off you go