The Apple P/N you require is 661-8310
Here’s the needed part [product|IF117-029-3] iFixit only has Grade-B & Grade-C used parts while cheaper do have some visible defects. TheBookYard in the UK has a new part for sale [https://www.thebookyard.com/product.php?cPath=39_368_371&products_id=12327|Retina MacBook Pro 15" Complete Display (13/14)] as you can see the cost is even higher! The older retina models are still highly sought as they have the ports onboard! Which is one of the reasons the price of parts is high as the availability of new parts is getting tight.