just from the little blurb on the Lodestone new feed

The collaboration between FINAL FANTASY XIV and the hit Japanese TV show GARO is set to end with the release of Patch 5.1, at which time the GARO inspired PvP gear, mounts, titles, and achievements will no longer be available.

so, I would think that you won't be able to get them since they will no longer be available come 5.1