Fortis Questions...

Evening Legends, I'm just trying to understand this watch... Bought it as a restoration project, only cost me £29, which I'm happy with for a few evenings entertainment, so this post is purely out of interest.

Fortis watches seem to cost thousands so is this a fake? Seller seemed to think it was from the 60's to maybe 80's, would they bother with a rep Fortis back then? Why is there a GMT case on it when it's not a GMT? Has it been recased?

I've opened it up and it's an FHF ST 96 inside, which I understand is a decent enough vintage Swiss movement. Would someone put an actual swiss movement in a rep?

My plan is to hopefully get this watch running, get a decent strap on it, and gift it to a friend, so it would be nice to be able to tell him what an earth this watch is?!

Cheers for any help you can offer