I got my bike second hand and it came with a factory X2 2022. I sent it in for a 2024. They shipped it to me today. Took about 2 weeks to get to this point. Hoping to try it next week.
But yes, they will warranty second hand ones.
Their website says
"If you have concerns about clearance with the link, we would recommend going with an Ohlins TTX22 M."
"If you are looking for a new shock to accompany this link, we would recommend going with the EXT E-Storia."