Changing from using manufacturer barcode to GS1 bar code

I have recently my first listing and got a UPC from GS1. However I didn’t provide this to the manufacturer and set up a shipping order for them to ship goods to the UK which are labelled with the manufacturers barcode. Should I change the UPC code in my listing to match the manufacturers barcode?
Also, I can’t select the Amazon labelling service unless I create a new listing, but I cant use my UPC on a new listing as it says it’s already in use, so I have to delete the existing listing before I can do that, but if I do so, will it give me a new FNSKU and will this cause problems with my order once it arrives at the fulfilment centre?