So I'm in the FM right

It's possible for GMs to send those kinds of messages directly to a player (and only to that player, or players). It's been observed before.

Although... this makes me wonder of how did they know the Facestompers were produced illegit?

i dont think a gm would ask someone to just drop something.. if they thought they were produced illegitly, they'd prolly ban the account or delete them. highly doubt it was a gm