https://www.alaskaair.com/content/on...-join-oneworld
This seems clear to me: "
When we join on March 31, 2021, Mileage Plan tiers will receive oneworld status, which enables the benefits of tier status recognition and eligible benefits across all 13 oneworld member airlines, providing access to over 1,000 destinations. For MVP Golds and Gold 75Ks, you will be able to access more than 650 international business class lounges within the oneworld member airline network when flying on an international ticket**."
I plan to hold them to it.