HT's has a very visible gap or seam between the top edges of the faceplates that, if you look for it, gives away that the mouth is removable. It looks like two pieces.
Have you read the preceding posts or just Maglor's comments?
I posted pictures clearly debunking the "top edge gap" theory.
I repeat, there is zero gap at the top of any of my HT face plates.
Please show me pictures of this gap on your figure.