Upgrading HDD on G-RAID w/ TB3

I have two G-RAID w/ TB3 arrays, one 2x4TB and one 2x6TB and would like to upgrade the internal hard drives to the largest possible. I read a press announcement from July 2020 (Western Digital Boosts Capacity for G-Technology G-DRIVE, G-RAID, G-SPEED Shuttle Products with 18TB, Ultrastar Enterprise-Class Drives | Western Digital) announcing new 18TB enterprise-class Ultrastar drives for these enclosures. Can I purchase these separately (https://www.bhphotovideo.com/c/product/1591087-REG/wd_0f38459_ultrastar_dc_hc550_18tb.html/reviews) and mount them inside one of my enclosures thereby creating a 2x18TB array without the need to purchase a brand new one?

Thanks for thew information oursainsburys