Will Square Ever Re-Run A Collaboration?

[Enkidoh]

Unfortunately the Regalia is not for sale on the Mogstation, I just checked '4 person mounts' there (which the Regalia is) and the only 4 person mount offered for sale is the Chocobo Carriage (SE did recently add the Lunar Whale airship from FFIV as the first 8 person mount to the Mogstation for sale however, which may be what you saw). There is also Cloud's Fenrir motorcycle from FFVIIAC for sale there as I mentioned previously which is sleek and black like the Regalia so that could be mistaken for the car at a glance.

So rest easy knowing that the Regalia is coming back in the rerun of the FFXV event soon, you're not in danger of wasting money so don't worry! (The first time the FFXV event was run, the Regalia costed a whopping 500000 MGP from a special vendor at Gold Saucer once you completed the FFXV event, so I recommend you start saving your MGP if you haven't already!)