My Book Pro hard drive help blue black gold?

I have a 8Tb my book pro and it has 2 Blue Se 4TB drives. Now the manual says only black, why I got blues I don’t know. So I know I need another blue to get my unit working again because you have to have the exact same. So my question is if I want to upgrade to 2x8TB hard drives should I use the gold because I can’t find the 8TB Blacks anywhere except if I buy a whole brand new one, which I don’t want to do. So will the Gold work? Using it with a MacBook Pro if that matters.

Hello, dra2000

First of all WD® do not recommend WD® Gold, Black or any other drive like Blue to be installed on the WD® My book pro, WD® Only recommed RED drive to be installed in the My book pro.
Well, If you want to upgrade the drive then you can follow the instructions mention on the manual.

Upgrading the Device Capacity: Refer to the page 20

WD RED Drive
https://www.wdc.com/products/internal-storage/wd-red.html