At one stage, Brabham had a link to an AC mod for this own the website for the BT62. Not sure if it is still there.
I just read that SRO is offering a GT2 entry for a modified BT-62. Won't see it til Oct at Paul Ricard, and that will just be an invite only to run the with rest of the GT2 cars. Soonest we'd officially see it would be 2022. I assume if ACC has any DLC plans left, they will add GT2 packs at some point.