Amazon US and Amazon UK – do UPCs need to be the same?

Hello again…

I sell my own product on Amazon, I have brand registry. No one else sells it. It is a unique product. I use speedy barcodes in the UK, I want to sell in the US and have opened my seller account / got brand registry. I will be starting the listing from scratch – can I use GS1 barcodes or do the UK and US account barcodes need to match? Will it present a problem later on if then don’t match? I am the owner of the product, I manufacture it, it’s my branding etc.

The product listings will be slightly different because of the descriptions (tailored to US) and also sizing (tailored to US).

Thank you!