Yes you can! The BRIN Blackout gets you automatically registered for all three races (Leprechaun Chase 10k, Cornfield Cornfield 10k and the Harvest Moon Hustle 10k). If you didn't get into the BRIN Blackout this year, you can still earn the medal by registering and finishing all three races.
Those that finish the Leprechaun Chase, Cornfield Cornfield and Harvest Moon Hustle will receive a BRIN Blackout medal upon completing the Harvest Moon Hustle race. To make sure you get registered for all three races, you can sign up for an email/text reminder for when registration opens.
Here is the link to register for reminders: https://pinkgorillaevents.redpodium.com/pink-gorilla-events-registration-reminders