Do Jade Reavers commonly drop for a CoM Moat group?

[Videri]

OP, I wouldn't buy a Jade Reaver.
To answer your question, they don't drop commonly for Moat groups.
They drop uncommonly from Black Reavers, which are one-groupable in the 50+ range and also a sort of introductory level mini-raid target.

If your guild can get a Pulsing Green Stone, your guild can farm Jade Reavers for everyone present. If you aren't part of an outfit that can farm Black Reavers, how will you get a Pulsing Green Stone? I think it will take much less time to join a guild and get a PGS and Jade Reaver than it would to farm all that plat and find sellers.

I wouldn't call the Jade Reaver a bottleneck at all. It's one of the easiest parts of the druid and ranger epics.