Obviously starting one and calling it 'official' would be a lie without at least the go ahead or stated support from the community here, but honestly even 100 people would be more than many of the groups and pages I have started on facebook, and it would be a place for me to gush over my favourite software even if no one else uses it, unlike here which would be redundant or reddit which I admit I dont even think of - the fact that people still use reddit is nice I guess. I did go looking for an OMPT facebook page years ago and found none but I didnt check now.
TLDR : if you start one (not recommended by saga) call it a fan page, there will be nothing official about it.