Talk to Brad at Matto Cycles (
https://www.gasgaspartsguy.com/).(570) 429-0678
I bought mine in 2019 - it took about a month for it to arrive, but worth it. It was a pretty good deal for ~$600.
Given the GG/Rieju changeover, it might not be available, but I've still had good luck buying parts.
Good luck.