It probably depends on what version of the Epic you are thinking of.
The standard Epic (not the Evo) looks to have an unusual specification shock (on top of all the Brain shenanigans- 265*52.5) and looking for standard shocks with those numbers doesn’t really yield any results from a quick search.
The shock is also described as ‘integrated extension’ which if you look at the images seems to suggest that the shock yoke is part of the shaft assembly. I suspect this would seriously limit your options in the future, unless some kind of work-around is created by third parties.
However, the Epic Evo seems to run a much more standard shock set-up with what looks to be a yoke that attaches to the end of the standard shock shaft.
This is just from looking at the specification on the website & the images.
Probably worth contacting a concept store or Spesh dealer for confirmation.